Ok, so Fire stronghold disadvantage states that you may not use any other quanta sources, but I am going to allow quantum pillars to be used for 3 reasons.
1) It will prevent an essential autoloss.
2) I did not include it on the banned card list
3) Because of last rounds rule legality derpiness, I will not change any rules/legalities until the beginning of the next round.
EDIT: Unless otherwise restricted, you may always use Quantum Pillar (specified in FAQ in rules thread).