You sure can. You can make a class full of homosexual women, homosexual men, bisexual everyone -- whatever floats your boat.
The only thing that you "miss out" on is 3P, which is only available in the case of 1xMale and 2xFemale, all bisexual. And even then, from what I understand (I've never played a male character, so I can't verify this myself) 3P in this game is actually just a short series of dialogue scenes and doesn't actually have an H animation to begin with. I personally can't imagine that it's worth the hassle to set up, though again, I have no experience with it.
The majority of characters in the
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are set to hetero, lean-hetero, or bisexual, presumably because this game's userbase is predominantly made up of heterosexual men, but you can always post-edit characters after downloading to suit your tastes.
This is probably going to be a dumb question, but I'm going to ask it anyway just to be sure: What are the characters saying after this fade-out? Are they mentioning anything about being scared, not being ready, or something similar? There might be a conflict with character settings. Virtue and/or lack of prior sexual experience (especially with anal play) can cause an NPC to cancel an H scene prematurely, which will cause a fade-out much like what you describe. Of course, the addition of modules to the mix can complicate things much further as well.