I did write a birthday cake item some time back that I will probably never finish (and honestly, a birthday system might be a little too much for the game as it doesn't add anything very significant besides a couple of unique events). Regardless, it had a template in it to spit out setting blurbs depending on your crew setup. It wasn't particularly waifu/husbando-focused since they were just there to celebrate Steele's B-day instead of doing romance stuff, but the setup of multiple character interaction was there to account different variations of crew currently on the ship.
It went something like this:
Posse (3 or more followers):
- Anno + Syri + Kaede + Dane = Who let the dogs out? Bow wow wow yippi yo yippy yay, DA BOMB.
- Anno + Syri + Kaede = The slutpuppies be all up in your grill.
Trio (2 followers)
- Anno + Syri = The doggie sisters do that thing they do fur yer berdday.
- Anno + Kaede = The girlfriends give you sex toys for presents because that's how they woof woof.
- Reaha + Gianna = Gianna and Reaha talk about New Texas and you learn how to be all awesome and stuff.
- Gianna + Yammi = Gianna and Yammi bring butt loads of ice cream to the party, yay!
Partner (1 partner)
- Celise = Celise is all like whlk whlk whlk!
- Reaha = Reaha is all like moo moo moo!
- Anno = Anno is all like bow wow WOW!
- Dane = Dane is all like arf arf arf!
- Syri = Syri is all like woof woof woof!
- Kaede = Kaede is all like woof hai woof!
- Gianna = Gianna is all like beep boop beep!
- Yammi = Yammi is all like blub blub blub!
The list is a bit outdated since I last worked on it, and I'm not sure if Kaede is ever part of the crew at any point, but that was something I had in mind when thinking that project up. Too many doge followers!
But yes, I agree that there should be more of a mixed bag, with some characters having a network mesh of interaction, compared to other followers who may have straight-linear interactions. We also might need to keep in mind that not all the people you put on your ship are there for fucking or romantic relationships--
but more often than not, it's the standard formula (because harem building is the one true goal!). So factoring relationships between other characters would definitely add to the experience, especially characters who are super picky with the kinds of relationships they'd rather get into.
If there is a guide to help take such interactions into consideration, I'm all for it. It can even range from just tiny scene blurbs to full-out choose-your-destiny type things.