1- Most likely. The taper angles have remained fairly standard 2* for decades but the "thickness" of the taper has seen some variation. This is why if not replacing with an exact duplicate one really needs to test fit. How deep into the crank arm's taper does the different axle reach and where the rings end up are the two biggies that can be hard to completely predict.

2- "Low profile" refers to the crank arm, not any specific aspect of the BB spindle, excepting the difference in overall length spindle length. Low profile just means the crank arm has a "s" curve to locate the tapered hole closer to the frame, thus a shorter spindle is needed. By how much...

3- Yes

4- Not me. back then I was a Campy guy.

Sheldon Brown's website has had a very good description of all this and how to measure the spindle (not how far into the arm that spindle will fit, though). I strongly suggest doing a little bit of reading before you spend any $. Especially if you go used, where returns likely don't happen. Andy