blizz waffles alot on this and subs, the original housing announcement is you would never lose your house if your sub lapses which i believe includes even if you use one token and stop. vets up to date on expacs should be good to go. F2P maybe will have access in two years
also have commented, if a player's account isn't active for a long time, the team may start removing houses when they aren't coming back, guilds housing lots needs 10 active players. drop below that or have too many go inactive guild housing will be removed, not sure if they plan on doing reminders to GMs