so..ven's heart is there although yen sid couldn't feel it. so maybe it's asleep? so if it's asleep maybe he can subconsciously summon it.
when aqua put him in the chamber of waking it somewhat awakened his heart and allowed him to connect to sora's (i'm guessing the chains and the heart symbol is to symbolize it?).
which leads me to the chamber of repose, which is chains connecting to nobody symbol...maybe, means instead of hearts connecting, it's body and soul? and xemnas talking to the armor which seemingly talks according to xigbar....maybe it's aqua's lingering sentiment? and i it...should lingering sentiment be considered special nobodies like replicas and whatever namine is?
sorry i'm ranting...this is best to be a thread theory or something