the explorer 8.8 will likely have an offset center if that matters for other stuff like exhaust routing, fuel tank etc. mustangs also have the 8.8 and have a centered pumpkin I think. lots have posi, disc brakes, an easy park brake cable system to swap over, etc. the pinion flange from an explorer can be swapped out to something with a regular u joint if you want. a stabilizer bar from an explorer or ranger can be made to work. if getting an 8.8 try to also get the complete rear park brake cable set up with the link between the cables and a rear section of the driveshaft so you can have it welded into your new one if you want to use the flat flanged pinion yoke. also, the brake hose, vent hose etc for mock up. the 8.8 can have the chev wheel pattern drilled between the ford pattern easily. a disc brake conversion and MII front end also means a master cylinder swap, replumbing brake lines, residual and proportioning valves etc, but you probably already knew that. the 8.8 is comparable to the 12bolt for strength so they say. check out the ranger station site for more info on that. the S10 diff is also easily sourced. maybe a good idea to choose some normal offset wheels as well so you can pick some up from anywhere without a custom offset. do a little drawing of the room you have between the fender flanges and the box/frame so you have it all figured out before you buy stuff. maybe also do some homework on gear ratios in the trans you choose so you will know what rpm's will be like for take off, rpm difference between gears, final drive highway cruising rpm etc. a more modern overdrive trans with more gears may help. just google engine rpm calculator and you will get something like this.
https://spicerparts.com/calculators/...rpm-calculator
for the front end, what will you go with for the MII? weld in, bolt in? if doing a weld in be sure to get the frame levelled and at the ride height and rake angle you want before you start. remember that if the truck is dropped in height it will change how the tires are centered on the wheel openings so some mock up would be good before a permanent change is done. block it securely and in such a way that the blocks won't be in the way for working but also so they will support the truck when the weight of the old parts comes off and the new parts go on.
post up pics as you go, ask for help if you need it. don't be surprised if you get some negative comments from time to time.