Again, my best advice is switch to 4Hi if you need wheel speed. Traditionally, trophy trucks which race through sand, are 2WD. Use 4Lo when you need the lower gearing
That sounds more like an issue with your son's truck than yours. It should be a very noticeable difference between the two. My old jeep rubicon was geared so low I could tackle most obstacles without touching the gas pedal.
I am on stock suspension running methods +25 with 285/70 R17 tires. No rubbing at all even when off road with wheels tucked.
As far as size, to limit any hit on MPG I would be looking for the lightest tire in those sizes. I personally run the Wildpeak AT4W's and have also heard good things...
I upgraded my sport wheels and tires to a much heavier 33” tire. Drivability is just about the same. Maybe a little more sluggish off the line but hardly noticeable. Once I’m moving it’s not really noticeable at all and braking seems mostly unchanged.
I find my sport to actually have a pretty smooth ride and I don't feel the back bouncing around over bumps like I have in other trucks. I also have C load tires but run 32/30 PSI
I got my wheels and tires from TireRack. They came mounted and balanced with hubcentric rings TPMS (for a small amount of extra $), and lug nuts included along with it. They also came very quickly, I think it was 3-4 days from order to doorstep.
Never owned a Tacoma before this one and I actually removed my rear seat for my dog but I think a center fold down armrest for the back seat would have been a nice addition. Add a little more comfort to a small backseat.