"If I go with two subs, one of them will have to be placed inside the bottom left compartment of the armoire( which would be close to the other sub placed outside the armoire), or on top of the armoire where the RS 1's are placed."
Maybe I'm dead wrong on this, but putting a sub inside of or on top of an armoire sounds like a HUGE no-no. It would seem to me like doing so would make the walls of the armoire vibrate and resonate and SERIOUSLY degrade the sound, and do MUCH more harm than good. I would not do this, or if I were to even consider it, then I'd at LEAST do an in home test prior to committing to purchasing the second sub.
The merits of one versus two subs have been roundly debated on this site before, but the dual sub option seems like a non-starter in the configuration you're describing. Even so, you may enjoy this thread from the archives:
One versus two subs--here's one of my favorites: Hilarious at times, but containing useful information too.