1. Negative, PACE iLok and Syncrosoft eLicenser are different and concurrent technologies, mutually incompatible, therefore no way to transfer a license from one type of dongle to the other. Changing the protection system is not a trivial task, and there are so much parameters to be considered. AFAIK, Arturia will not switch to PACE system in any future, we will stick to Syncrosoft (USB or Soft).
2. Yes, of course.
3. The Updates page always list the latest version available; thus it is the best way to (re)install your synthesizers, from scratch or for update.