Blend trees can be tricky to learn at first but once you get used to them you find they speed up your work and you have to spend a lot less time managing animations. ESPECIALLY if you commit to root motion and using AnimationStateMachine Nodes. it's like cheating haha, animation driven movement can end up saving you so much programming time. I have some videos and templates on that sort of stuff if that's handy to you (here on itch, and they link to youtube)
The baked lighting though! I think for your game itt would have been killer. Like throw some windows on that house, and a dark skybox, then bake the lighting, and add a reflection probe too! WOW it can make a game look amazing fast. Especially int he case where you're a first person ghost and so dynamic shadows don't matter so much. It'd be really great. Let you add more ambient dramatic lamps or something, push the look of the candles, etc, all while saving on performance but turning off dynamic light.
As for music, i think just some a light, spacious, gentle, high piano part. Something just noodling some nodes lightly would be all you'd need to get the ambience of a sad, lonely home.
Thank you for checking is out! Unfortunately the support for (baked) lightmaps is still missing for the compatibility renderer. High hopes for Godot 4.3 to reimplement it.
Can check how it would look on the dev build just out of curiosity, but figured it's better to release on a stable build of the engine.
Another option would be to bake it into textures, yet that would've eaten a lot of time that we just didn't have.