Okay... finished my second playthrough, and ended up with optimal endings for everyone. Protip: Quicksaves, rollbacks, and saves are your friends. ;P
I'm pretty sure I may have missed only a couple of (very minor) scenes, but I'll definitely be playing through again.
I dabble in Ren'Py a bit - I wish the scripts weren't compiled so I could just add my own image and scene galleries (for my own "purposes", heh) - since it doesn't sound like galleries are going to make it into the final release. =(