You'd be eligible for FD, just can't combine both offers.
If FD comes out for your dates you can price that out too see if it's better for you and can switch to that if the room is available for the FD promo. Of course if you take FD you lose the Monster room discount. Got to do the math to see what works for you.
Booking one offer doesn't mean you're stuck with that offer if a better one comes out. You can even switch after your final payment date and get a refund less the $50 revision fee for a lower cost package.