Hehe I love Aseroe I think they're very cute and they have no idea. It was fun redoing their sprites for the current version of Squid Girl World because I like how they look now.
Regarding their wings, it has to do with where they're from, but they're averse to discussing anything related to it though other characters can figure it out sometimes.. Aseroe just.. will not discuss it even they know someone else has realized.

I love Nettle. I excited for when he comes back (SOON). He'll be in some more episodes... Nettle would probably get along with Adelaide. Adelaide likes masculine lesbians in general and finds them useful, and she'd appreciate his strong convictions. Nettle likes other prickly people. It's something he respects and they'd probably be really Mean To Other People LOL.
Things about him. He has his own ship and he loves it much like Aseroe loved theirs but he likes his to a greater extent. Much of his behavior is based around morality which is one reason he doesn't care for kindness. He thinks kindness is expressed not through niceties or pleasantries but actual acts of good.
They seperated probably mutually because of basic incompatability. Nettle lives a life likely focused on ethical duties while Sepia lives a life focused on hedonism. Nettle struggles to tolerate this mindset in a longterm romantic partner, but Sepia gets agitated from any sort of tension.
They're still friendly for this reason lol. They both are (mostly) mature people who recognize that they just have different core beliefs on how to exist, and they probably were still intimate at times before Aseroe's arrival LOL. Not every time Nettle checked on Sepia but surely sometimes.. Sepia.. Sighs..

It's the lyrics.. Sucre does not want to listen to that particular song, but the other songs Snow listens to are likely like this even if they're not all by Tom Lehrer.
I imagine her listening to one other song in particular he absolutely can't stand but I won't say what it is because I hope to include it in a future episode someday. It was in the original draft but So Long, Mom just feels really good there for a variety of reasons.

Aseroe probably was confused and perturbed about Sucre's treatment of them, but it's because Sucre clocked that Aseroe had autism very quickly for reasons and well.. The way Sucre treats Aseroe extends to many aspects of their relationship, so it's something they enjoy from Sucre in particular but they dislike being babied by others.. But Sucre is good at allowing that not to happen.
Sucre distanced himself for a variety of reasons but the main reason is because he was doing other things LOL and Snow lowered in his priorities as time passed, especially after they broke up. Sucre spends the most time with his partners or doing other things related to romance and intimacy because of the kind of person he is, even without Aseroe at times. He's basically always romantic and touchy feely, but it feels awkward to do this with someone who is very emotional about you...
He still deeply cared for Snow though, but .. He and Snow grew up together then went straight to Reaper Training, so post training, you know.. he wanted to live his life haha.

he's one of my favorite characters... squid girl world is one of my favorite works to write even if it is in constant state of wip.. thanks for the question!!