Basic lift and first gen Toyota tips

My name is Austin I'm a big jeep guy ( I know I know but I love her and I respect all offroaders my uncle has had 2 land cruisers and a t100 that he used as a dd while he worked as a hunting guide and we have gone all over Wyoming back country in his landcruiser and it took it d**m well ) my good friend is looking at buying a first gen 4x4. So I have some questions what is the proper and most ideal caster angle and what is the Max amount of lift without having to do new driveshafts or severe drivetrain modifications. Second I would like to know when regearing the ifs do you just regear the rear or do you regear the front also and if so how do you do it. Third is what is the max tire size with out having to do major beefing up of the suspension , rear dif, front ifs, and brakes.
And my rig is a 08 jk with 2.5 teraflex on 35 km2 lighting etc (please no jeep bashing I always have liked toyatas and I've seen just how capable they are and I'm simply helping a friend who wants a first gen Toyota 4x4 and is not aware of how much effort who goes into making a safe capable rig
Thanks
Austin