I wasn't able to find any 14" tires in LRD when I did a quick search. If you are willing to move up a size to 15", it might be a bit easier to find LRD and LRE tires. I'm running a set of Greenball Towmaster SS tires (from Costco). I put 4 on my 24' Prowler (ST205/75R15 LRD) and have towed about 3500 miles so far this fall on them without issue. Speed rating is M (81 mph).
You should be able to straighten the hanger with a large crescent wrench (like the 24" one that Harbor Freight sells cheap). Use a long straight edge to line it up with the other hangers so everything ends up parallel. I'm not sure I agree that a bent hanger means a bent axle. Straighten the hanger, then remount the axle. Take the wheels off and take measurements from both axles. Compare the squareness of the machined hub faces to the frame rails. You can get additional information from the Dexter Axle Resource Library (http://www.dexteraxle.com/resource_library_). If an axle appears to be out of line, it can be straightened by a good alignment shop (for less money than a new axle). Remember, a replacement axle may not come with the axle perches welded on as the spring center-to-center distance can vary per the trailer manufacturer. That would add to the cost.
Best of luck with the repair- keep us posted on the results, please.
When I raised my trailer this past summer, I found the 3500 lb axles (assuming you have leaf springs, too) use a nylon bushing in all the springs and equalizers. I replaced one equalizer and there is still a bit of slop in the springs from side-to-side. So, I am paying close attention to my tires and so far, no funky wear patterns.