[dsraven]

whatever cab you use, check the door hinge pillars and the cab mount area for rust and rot before you get too far into new frame mounts for the cab. I suggest to ensure the pillars and cab mount metal is good, door hinges are tight, then get the door fitting in the opening well (without latches, so you know the door swings into the correct spot when closing and the latch isn't doing the final fitment work) before taking the cab off the old frame. that way it is sitting in it's original shape and the doors fit like they are supposed to BEFORE you change anything. then set the cab down on the new frame and block it up where you want it.
just my thoughts. it's your truck and your plan. I just know from experience that these old cabs have a way of sneaking up on you with unknowns AFTER you have work done. don't assume the door is sloppy because the hinges are loose. sometimes it's the internal door mounts for the hinges that are cracked and sometimes it's the hinge pillars that are rotten. sometimes it's the hinges that are worn. put it all together and it's a lot of work you didn't know you had coming.
nice find on the big truck cab, they are usually in better shape due to ground clearance and a lot of them sit the winter season out due to less work load. still, the water/melted snow etc gets through the cowl vents onto the floor and causes rot issues with all these old 55-59 trucks.
for lifting the cab you may consider a spreader bar so the cab gets lifted straight up instead of the possible "squish" provided with the strap method. I included a pic of how I made a spreader for the engine lift and it could easily be modified for your scenario with the skid steer. just an idea to consider. the strap method works too, obviously.