Best way will be to give 2 FW?
So i can vote for flash Android or Sailfish. Also Nokia/HMD can view access of FW-Downloads to evaluate if it is a market for Sailfish.
Obvious Sailfish has to add feature like SIP, VPN and so on.
Best way where if the EU give financial support to push a non US OS.
But i think it will be more possible a new Russian OS (base on maemo) :/