[M/T 4 F/T] Unconventional incest

[FM]

I'd like to do these over PM. Contact me that way if you're interested, please.

I'm not looking for anything particularly literary and serious, but I'm not looking for mindless smut either. I love detail and backstory, and characters that have personalities and do more than just have sex. At least in the case of these plots. 

And, this is stupid, but I kind of want the female characters to look a particular way. I may have several suggestions.

The Mitchells

The Mitchells (can be changed) have been happily married for twenty-something years, and have a daughter or two together (19 and/or ~24). The husband is having sex with their daughter(s). His wife is aware of it, and she's cool with it. And even though this is going on, her husband's still attracted to her, and they have a healthy sex life.

I'd like this to be more than just sex between the father and daughter(s). I'd like there to be scenes between the parents, and a lot of completely non-sexual scenes. They're all fucked if the God of Abraham is real, but they're still a family, and I want that to show. That goes for all the plots in this thread.

Moms

Two women in a same-sex relationship (not necessarily a lesbian relationship) adopt a young boy. A decade or two later, he's in his early twenties, and neither he nor his mothers think of him as an adopted son -- they all love eachother very much. But for the last couple years they've been expressing that love in ways that aren't very family-friendly.

Taking Care of Grandpa

A young woman lives with her grandfather, ostensibly to help him around the house and whatnot. She does help him around the house and whatnot (he is old), but that's not the reason she volunteered to come live with him. She's been fucking with her grandfather since she was at least sixteen (somewhere between sixteen and nineteen), and this seemed like a good plan after years of sneaking away at family get-togethers.