Before you start your teardown, I have one more suggestion for you.
I was having the same problem freeing some stuck pistons.
I read an article somewhere about various chemicals to loosen stuck fasteners, etc.
It turned out that what worked best in the article was a home-made mix of acetone and
automatic transmission fluid (50-50). I made some up, added a couple ounces to each cylinder, waited an hour or so, and put some pressure on the lever I had wedged
into the rotor of the alternator. It took maybe 30 lbs force on an 18 inch lever to break
it free! I'd tried many other chemicals, and a whole bunch more force before that, with absolutely no luck. Give it a try!
Bowhunter