Can't put wheel cylinders on the front if they are disc brakes, and i am sure they are. But i like your thinking....get new calipers....chances are if they are that rusted, time for new ones anyway...but if you don't want to go that route, get a 6 point 7/16 socket (i think that is the size if i remember correctly), not some taiwan socket...craftsman's good. And as mentioned, put a little heat on it w/ a propane torch...but be careful w/ that...you can ignite the fluid, that would be bad. She'll come off.
You can bleed your lines through the brake line as well....don't even need the bleeder screw. Just loosen the line a little and it acts the same way. It'll get 99% of the air out...there may be some air in the pistons that it wont get, but it'll do the job good enough.
SgtDel