Thanks. I did some searching and would only have to rent/buy Cap 1, Cap 2, Ironman 1, Thor and GotG 1 to do my condensed rewatch. $15 to rent them all isn't bad so I'll do that. I hope they have them all available for streaming whenever Disney+ is released.Iron Man 2 is currently on Hulu and Amazon Prime. Iron Man 3 is on the FX App (if you have a cable/live TV subscription). Avengers 1 and 2 and Ant-Man are on SyFy (again - cable/live tv sub needed).
That's just from doing a quick search on JustWatch. I didn't see the Captain America movies (1 or 2), Thor movies (1 or 2), Iron Man 1, Incredible Hulk, or Guardians 1 available anywhere. Still, with the above, you could save yourself a bit of money.