Most of these ideas might seem random but I feel that if I get it out we can frame it anyway we want.
First, I have to agree with you as far as some of the thoughts that I've received from writers who are scared to dabble into the realm of interracial romance because they are afraid to "get it wrong". I also agree that I've read some very stereotypical portrayals of characters of color in some erotic work.
However, I think what might be interesting to chat about is the fact that, since we are both writers of color, how we approach creating our characters. With both of us being African American, how do we approach characters outside of our race when we write? Also, since we both live in big cities (I lived most of my adult life in either Washington D.C., New York City and Los Angeles) how does that affect how we look at interracial relationships.
I write a lot of interracial F/F, ménage and group stories and I use a great deal of my experience growing up in a multicultural world for my characters. I've had friends of all races and religions that have allowed me "insiders access" to their lives. I use the information when it comes to creating characters. Even as I'm writing this, I have stories out there which have East Indian, Latino, Asian, African-American and Caucasian characters.
I understand how a little bit or research can go a long way but I guess the question that I've always found interesting is, if you’re a person of color, when you think of writing romance do you think of character traits or race first?
For me, I always think of character first but most of those characters happen to be people of color because that's how I see the world. I'm not sure if this is true for everyone and even with there being a rise in interracial romance readers are there certain genres that lend itself to a "slippery slope" when it comes to placing an ethnic spin on things?
A perfect example of this would be BDSM. Personally, I enjoy reading these stories but whenever a character happens to be African-American, I feel that I have to look at the character with more scrutiny. Especially if that character is a sub. That might seem a little petty but I can't seem to let go of the history when it comes to the imagery. Whether that character is male, female or transgender there is a part of me that tip toes through these stories trying to not allow the action to carry a specific meaning other than character wise.
The same goes for cuckold stories, which have a tendency to lend themselves towards more stereotypical imagery. Even if the "Big Black Bull" is a three-dimensional character, the idea of the "Big Black Bull" still carries a historical connotation that has me wondering more about the author’s intent rather than the validity of the story. (Also, most writers forget that the idea of the cuckold comes from the female dominance of the submissive male and not the lust for black male sexual power re: Venus in Fur)
I've found a few stories that have been able to capture a balance between character and the historical implications of putting character of color in situations like this but they are very rare.
The same thing goes for the submissive Asian female character or the over sexed Latino.
I guess the point is that if the motivation is clear that the actions are coming from a character perspective then the story should work but you can't deny that the ground that you're walking on has all type of landmines that might turn the reader off.
That's not to say that these stories can't work or that they can't be written by authors of different races but I feel that sometimes the urge to try and embrace everybody by saying that race is only skin deep doesn't take into account that the perception is in the eye of the reader.
For me, I try my best to be all-inclusive and conscious of these elements when I'm creating characters because it’s difficult for me to think that a characters physical description is only the way that character looks. It has to be all of those elements combined that makes them three-dimensional.
For my story "Umoja Mean Unity" that was in "Doing The Naughty List, Twice" my MC was half-Jewish and half African-American whose family celebrated both Chanukah and Kwanza. Since this was a holiday anthology, the idea of having a bi-racial character fit perfectly but the balance between the two holidays and how it made my MC unique came from both personal experience and a great deal of research. I didn’t think twice about “if” I could write this character but I also understood that striking the right balance between her religions and ethnicity was important to get the story across to the reader as well as keeping her unique and three-dimensional.
I haven't been writing long enough to notice how stereotypes play in f/f writing as of yet except for the Sapphire Black Woman which I try to avoid but I love writing strong female characters who know what they want. It came up in my free read today and I spent a lot of time trying to work my way around it but that is who my character is so I'll stick with it.
I also feel that religious diversity is an area the gets ignored as well. I'm working on a book idea that I'm still researching a great deal about two Jewish women who fall in love in New York. One happens to be Mexican and the other Ethiopian. The fact that most people don't know about the Orthodox Mexican Jewish Population is amazing to me since I've know a few and I'm neither one of those.
I worked in an Orthodox Jewish neighborhood for three years and the rules that designed to keep men and women apart lends itself to exploring same sex relationships but it's also a very slippery slope. I know I have enough experience for the other side to fill in the blanks but I still have a little bit of pause about starting to move the story forward from the outline stage.
However, I still feel that if it's all about diversity it's hard not to think about the physical being an important factor but as you said, it has to be more than just about the color of a characters skin.
I understand how some stereotypical behavior can filter into a character and I don't mind that if it is justified by back story but what I have a problem with is a character who just seems to be there because the writer though it was a good idea to have a character of color in the story just because of potential profits.
I guess if you show me your writer's hand when it come to creating interracial relationships then I feel it's fair to questions the "whys". And if your response is that I should be able to write about whoever I want to write about then you should be able to accept that fact that I should be allow to point out the fact that your ethnic character lacks "character development".
So, I guess all of this is to say "What responsibility does a writer have when they create ethnic characters?" or "How do you get your interracial relationships right in erotica?"
I teach screenwriting at a major university out here in California and my focus for the past 16 years has been character. I'm a playwright and screenwriter as well and when it comes to developing characters, the 3 most important questions are "what does you character want?", "what does your character need?", and the most important questions is "why does your character want what they want?".
I used to work at a small talent agency and every time I asked that last question they would look at me like a puppy who just peed on the rug. And these are people who make their living writing for the screen and TV.

In New York, the neighborhood was segregated but traveling through the city wasn't and that's why I cherish the years I lived there. Los Angeles is very segregated which might seem strange but as you're driving around the city you will see the color of the faces change block by block and since everybody drives here so it appears a lot worse than what it is which is still pretty bad.
I have to agree with your last ideas as well. I do feel that writers have a greater responsibility to do historical and cultural research before writing their stories and the people who criticize about writers "not getting it right" as assuming that everybody's experience is the same, which means they are denying the possibilities of characters and focusing on the limitations of their own experience.
True, we as authors should focus on the plot line of our stories but why do we have to justify using ethnic characters in our stories when the same doesn't apply to non-ethnic characters? That means if you use a character of color, the plot must be focused on the character being a specific ethnicity. I don't feel that's fair but those are the rules that we have to play by, I guess.
On a side note, the thing I found most interesting when developing my story about the two Jewish women was the fact that Latino food doesn't lend itself to being Kosher. Especially when it comes to Orthodox Kosher food. There is a point in the story that I've outlined where that gets challenged when my female Mexican character has to deal with this issue at work when they have an office meeting that is catered. They decided to get Mexican food for the meeting and she can't eat any of it because not only was pork used but the combination of meat and dairy together which is a major violation of Kosher law. With this one I want to make sure that I get the religious aspects right because I got a intimate glimpse into the Orthodox world from a woman's perspective yet being an gentile there are still some places that I wasn't able to get to due to the secretive nature of the Orthodox religion. I understand the concepts but knowing where they developed from in regard to the Torah is where I'm at now. I hope I can get started on that one by the end of the year.
Since the genre interracial had "race" in the title it should mean that race play an important factor in the story. However, if it doesn't and the characters happen to me of different races does it still make the story and interracial one?
I guess what I mean by that is how is the term defined by the writer vs the editor/publisher vs the reader. Perfect example would be if a Japanese character fell in love with a Pacific Islander would that technically be an interracial story? What about an East Indian character who falls in love with a Pakistani? Where is the line drawn? The Irish and the English are both Caucasian but the differences in the culture is vast, yet if they fell in love it wouldn't be considered an interracial relationship.
I rambled to say I supposed yes it still would be interracial because they aren’t of the same culture. When we'll be able to get passed that culture divide and just appreciate each other for our unique traits. I dunno. I suppose we’ll be waiting awhile.