The one with neutral cable hidden that you have mentioned, neutral is usually black color... (green is earth). Better confirm this first?

I did this with whatever is next to switch (be it A/C or 3-pin sockets), under assumption all N goes direct to same connection point at the db mains.

Your 2 gang the green wire I think more like earth wire than neutral? Usually earth is green, live is red/yellow/blue, neutral is black

Depends if later u will expand your smart home or not or just going to stop at 3 switches, if 3 switches than cheapo wifi switch 2 neutral 1 non neutral can d, not recommended to borrow from ac, ac may be different phase eg. Your live is red, ac may be blue then the neutral will be diff phase, later you will headache if u want install RCD for each phase, but if u don't plan to do that usually no issue la. Non neutral cheapo switches will need to install the capacitor, for this you need to know how to disassemble your lights / fan to install the capacitor. Good thing with cheapo wifi switches is that it's cheaper by half, spoil just throw and replace

Aqara D1 no neutral switches are the better ones, no need use capacitor like some others.

Also to note, Aqara have 20A switches. I’m using Aqara M2 with Zigbee. Pretty solid and stable, though I’m using neutral switches which acts as repeaters for the signal.