Hmmm,
The $1200 to replace 8 bearings and 4 grease seals and service the brakes which, I'd think means replace the emergency breakaway function seems high.
I'm assuming the overhauled axles part of the quote, $2300, includes 2 new axles, new shackles, new perches and leaf spring bushings that would be aligned during installation. If I'm correct in my assumption, that seems fair.
If I'm incorrect and they aren't quoting 2 new axles but rather quoting $2300 to cut off the 8 shackle perches, (attachment points) weld on new perches, replace the spring bushings (plastic type material) and shackles using the original axles/springs also seems too high.
Axles aren't too heavy, 1 person and a floor jack can easily position them. 2 people make it go a lot faster, Alignment is usually done by carefully measuring left and right and forward and backward.