1. Only if a tire(s) shows a abnormal wear pattern similar to yours. The wear pattern sounds like a bent axle stub or the axle tube, allowing the tire to lean in at the top causing the inside of the tires tread to wear. A large big rig trailer repair shop can bend the stub or the axle back to specs. I've had more than a couple of my equipment trailer realienged this way when a axle gets bent. No issues.
Or it can be a tread belt seperating causing the tire to wear that way.
2. When replacing tires on a trailer the owners only responsibility is to have enough capacity for the axle load which is usually the same as the axle ratings.
If you have 6k axles or smaller any of the LT E at 3042 lbs work great.
If the axles are 7k the Goodyear G614 @ 3750 lb works fine.
Some folks move up to the 17.5" wheels and commercial grade LT tires.
I wouldn't put a ST tire on a trailer that size.
'03 Dodge 2500 Cummins HO 3.73 NV5600 Jacobs
'98 3500 DRW 454 4x4 4.10 crew cab
'97 Park Avanue RK 28' 2 slides