About question 1. I tolk about diferencal lock like bouth front weels are lock and bouth rear weals are lock and turn together, NOT only one af them. ???
Yes, you mean differential lockers. I know Aussie makes them for both front and rear. The Aussie lockers are automatic locking also known as "lunchbox" lockers. They run around $300-400 per set. ARB also makes air lockers which are around $1,000-1,200 per set, plus installation. You will want to consider getting some AISIN or Warn locking hubs if you want to be able to drive it on the road safely and plan on being able to engage and disengage the front wheels.