First of all, thanks for all of your comments! I need to learn a lot :) It's hard to wrap up all of my additional questions, but I will try.

I'd rather have veils
I would go with Mutable Veils (2020 version)
Get a MI Veils (V2) for a VCA

I bought last in the World Veils, so I'm doomed and my modular sync adventure has started ;)

case is weird size if you are actually building it - 84hp or 104hp rails are easier to buy - and a better size - especially the 104...

Yes, I want to build one. I changed its size to 64 because this helps me think small, I want to build 6u x 84hp case. My idea is to start with ~10 modules.

you do have too many sound sources to start with and too many in the long run in this size case
I'd also take a look at your end of chain (eoc) mixer - not enough channels for what's in the case already... no send/return

I removed Cs-L, so Plaits and BIA as sound sources. I decided for this mixer because it has headphones out... Right now I think that it's better to have separated modules for mixer and for headphones to have more creative possibilities. 4 channel mixer (with some stereo inputs) will be enough for this or I need more? I'm not quite sure about this Stmix from Befaco.

For ambient, look into Zadar.
Xaoc Zadar is great for envelopes.

Yes, this is much better option than double ADSR. Do you think that I should replace Pam's with this module or this is just great addition to Pam's features?

the multi-fx, which I'd replace with an fx aid pro

Fx aid pro has bazillion effects but only 1 channel, more to explore but one sound sorce at the time... Tough decision.

This is my second approach, but I still think that I'm missing things. Some more utils needed. But I want to limit myself to 10 (max 11 modules) and try not to cross 2,5k euro.

ModularGrid Rack