Questions about Lightning, Navigation , Tutorialsource

hello,

i have basicly three questions :

Dynamic Lightning vs Baked lightning :

Is there a quality difference ? How big is the perfomance difference ?

Ai navigation in a random generated enviroment: Lets say :

You are in a lobby with your friends , and everytime you join a game a completly new map with ai events objects etc is generated.

Could the AI navigate in such a enviroment with unity ? it doesn't have to be at runtime, just before the players join the map.

i think hellgate london is similar, but i never played this game.

Tutorial Iam a programmer since 2 years and i know c# , i also know some basics from unity 3. what tutorial would you recommend me to read / watch ?

Would love to create an enitre game per tutorial (simple).