If you are the last nation in a region that is passworded without it being visible to residents are you able to request the password be removed? I am wondering since I have come across some old regions with the remaining member in that predicament.
There's not quirks or exceptions. Moderators will not break in and open up a region that you want saved on request. That is a political manoeuvre, not a rules-enforcement one.
If you are the last nation in a region with a password, and there is no governor to remove it or the governor is unwilling/unavailable, your only recourse is to seek the intervention of a Security Council liberation. If you cannot get the political momentum to unlock your region in this manner, then you will have to remain in that region indefinitely to sustain it.