Tyre brand and size, LOL

There simply is no correct or consensus answer to that. Do some searches and you'll find what you need, what I will say is that most of the offroad tyre development dollars in the last ten years have gone into mud terrain tyres, which now leave all terrain tyres for dead on tarmac - I wouldn't even consider all terrains if you plan to go offroad every other weekend.

There's a new generation of all terrains starting to come through which will redress that, of course.

285/75R16 is the best size for a GU on 16" rims in my opinion (and drop to a 70 series for a 17" rim).

The biggest question is "white letters in or out", LOL

Welcome to the forum.