I hate to be the one to say this, but your trailer need professional help. The only way I know of to "straighten" that I-beam frame is to cut out the damaged section and replace it.
Of course, that will require a "frame machine" to keep everything else true...
Hopefully others here can offer better ideas.
As for the wheel not spinning freely, you probably bent the spindle that the hub/drum assembly rides on. If that's the case, replacement is the only cure I know of.
(It looks like the tire was rubbing the inner wheel-well in pic 2277...what's up with that? Did the tire blow-out?)