Does anyone know if 15" wheels would fit? (I've got a 2014) I've dug through a lot of the forum trying to find anything, maybe my search skills are lacking.

I'm looking to fit AT tires that are significantly taller than stock as well as a suspension lift to get a bit more ground clearance.

15s are problematic to fit. Most won't as the brake caliper will hit, but there have been a few people that managed it. You best bet is to stick with 16s.