Dumb Questions about Cooper Discoverer S/T Maxx 255/85R16

I'm near pulling the trigger on the Cooper Discoverer S/T Maxx 255/85R16 as my first set of replacement tires on my stock 2019 TRD Offroad 4X4 M/T. I have a few dumb questions. The first question I have not seen answered on here, nor could I find a clear answer on google. The second question has been answered a million times on here but if you could answer it one more time I'll have the warm fuzzies about pulling the trigger.

1. What does the S/T stand for? When I've tried searching on google, the only result I find is that ST (not S/T) stands for Special Trailer tire and should only be used on trailers. Surely that is not what the S/T stands for right?
2. These will definitely fit my stock tacoma right? My current, stock, tires are 265/70R16. These tires will fit my stock 16" rims even though they are more narrow, correct? And will fit my stock truck without rubbing?
3. Do I really have to replace all 5 tires or can I keep my spare 265/70R16? If I get a flat, how bad would it be to run 1 265/70R16 and 3 255/85R16's until I get the flat tire repaired or replaced? I'm guessing it wouldn't be too bad to run for a day until I can get it repaired (if repairable) but pretty bad if I had to drive like that for weeks waiting on a replacement tire to ship. I think I remember reading in a thread on here that the 255/85R16 spare fits fine underneath the truck, correct?

 

I've got these on my 17 Pro, stock wheels, stock suspension.

1 - no clue
2 - yes-ish, it'll rub slightly at full lock and full stuff when reversing quickly backwards uphill (like on my driveway)
3 - no, see the link in my signature, yes it fits

 

Stay out of 4 wheel drive when driving with assorted tire sizes.


255/80-17’s

 

Thanks for the info:
2- Dang. I've seen a lot of comments here from people with TRD Offroad say it doesn't rub under any circumstances. A little concerning that yours rubs slightly in a TRD Pro. Doesn't the Pro have an extra 1" of clearance?
3- Looks like a lot of disagreement in that mismatched spare tire thread haha. Some people say it's fine. Some people say it's fine in 2WD but not 4WD. One guy said it puts a lot of wear on the open differential and 200 miles with the mismatched spare will cause wear on the differential equivalent to 20,000 miles of normal driving. I might just bite the bullet and buy 5 tires to be safe.

 

I thought so too for a long time, but eventually the geometry catches up. You've got to try to get it to rub to make it happen. I would say it's so rare that it's not a reason to not get them.

For the spare - it you're unsure about it, can't hurt to get a 5th.