I finally managed to convert mom to a relaxed mother yesterday. It was a major effort. Big Sis actually has the most content though even without having a new archetype to move to. The only new scene I could find for "relaxed mom" is the option to peek on her in the bathtub in the morning. Otherwise it looks like she just changes her outfit.
I don't have all of the stats maxed so there could be stat gated scenes I haven't seen yet but I think the main ones that matter so far are incest level 1-2, stealth level 1, and humor level 1. If you use the video games start then raising either fitness or charisma to level 1 for the appearance boost is needed to talk with little sis as well which means grinding through to trivia level 1 first. I actually still liked the video games start the best anyway though because the focus boost is so useful.
Also a comment on the outfits. I'm hoping Baal doesn't fall into the trap of having a separate outfit for every archetype. That basically forces you to make a separate copy of every event that character is in for every outfit they can have and then go back and add new copies if you add another archetype they can have later. A few different ones isn't that big of a deal but I suspect the plan is to eventually have a LOT of different archetypes as new characters get added. I'd like to see more of a focus on adding additional options to scenes depending on the archetype rather than redoing an identical scene with a different outfit. I could see having groups of archetypes all share the same outfit though for each character. So maybe there's something like a prudish outfit, a casual outfit, and a slutty outfit or whatever.