Chant, 1 of your axles are out of alinement you can see the difference between your tires on both sides of the trailer are different that's why your tires are wearing funny
I think the brakes on those wheels/tires that are worn might be a little tight. There is no real way to adjust the gain on individual wheels. I'd recommend getting 16 ply tires when you replace. Best to replace all 4 at once and keep the 2 good ones as spares. You might want to consider balancing them with COUNTERACT balancing beads. This way the tires will balance themselves as you drive for the life of the tires unlike regular lead weights.
When you go to get new tires, You can get the balanced just like regular tires it'll safe you a ton in the long run! The music was fire this time around! Are you looking for anyone to lease on with you? I am interested also 14ply and 16ply tires are better