Not sure about the ABS cleaning, but I would take a trouble light and look into the wheel wells. If anything is loose/damaged - that is a more likely spot.
Regarding the AC hose and recharge.
R12 is about $100 alone, assuming you have to go to the indy for the stuff. If you put it together and it still leaks, it becomes your problem to fix and you are probably going to pay the mechanic to fix the leak and recharge (again). If he fixes it the first time, it becomes his burden to make sure there are no leaks, and you only pay for the 1-time recharge.
( I just hope this does not start another thread about R12 certification, or the dreaded "bring your own parts to a mechanic" discussion