I'm partial to the BFG KO's. Below is a video I shot about a decade ago with one of my S10 Blazers on the BFG's. Drove it through a field with 8" of fresh snow. Plus a snow bank. They never skipped a beat. I used to pull people out of ditches with that Blazer. Even pulled a local cop out of a ditch and pushed another off the road, he got stuck and was blocking traffic. The KO's are awesome. That was back in my off-roading days.
https://www.youtube.com/watch?v=T6urte0ooRg
As for the tire size change. Back in the day we used to change the speedo gear in the transmission. But with today's computer controlled engine/transmission management and ABS systems, that change is made in the on-board computer. Your dealer should be able to make that change no problem, $$. As for fitment, you'll have to do the research. Check with truck forums, or off-road sites. "Upgrading to bigger tires" is a common modification. I stuffed 33" tires under an S-10 Blazer. Granted I trimmed the fenders and had to beat the firewall back a couple of inches so they fit, but they fit. lol
Short video of the S10 on 33" tires. The tires were Cooper Discovery Series, SST if memory serves me correctly.
https://www.youtube.com/watch?v=af7Vc6OZakI