The engineers only care that it survives through the powertrain warranty. Can't speak to the ecvt, but after changing my 8 speed at 30k'ish miles and seeing what it looked and smelled like, there's no way in heck I'd go the recommended change interval.
Depends on the tire I guess. Dimensions vary slightly for the same size from different brands. Don't recall what brand I bought, just an off brand a/t tire, but it's under there, hitch and all.