All creatures listed in config/creatures/.
Check WoG mod content, creatures.json.
Something like that could only be coded in C++ at moment. Eventually we’ll have scripting support.
Stack experience and few other are implemented in VCMI, but I never tested it.
Resurrecting can be added as creature ability. E.g check archangels config and copy it to first aid tent.
Towns and creatures you have depend on what mods you have active. Long time ago VCMI required WoG assets to work, but it’s optional for long time.