A DANA 44 should suffice with a gas motor however; diesel can be very heavy so then it would require a shortened DANA 60 like the ones used in aftermarket jeep applications.
Depends on how you drive it and use the truck. Common in the rock crawling groups is that 35"s and smaller tires are fine with a GM 10 bolt/Dana 44 with most drivers.
You're pretty limited with the S10 unless you swap the rear as well. The 5x4.75 lug pattern is an odd ball. That said, I've heard of people using dana 30's out from under a JEEP. I believe you can swap the GM hubs into the JEEP knuckles to keep your lug pattern, but the dana 30 is not a very stout axle. Many have used the dana 44 out from under a late model grand wagoneer, but then you're dealing with the 6x5.5" lug pattern. Otherwise swap in a set of half ton front and rear axles and get wheels with the required offset to bring the tires back under your fenders.