This might sound kinda mean, but... honestly? I logged in, cleared the first 3 raids in about an hour, and there were still plots left for sale in Shirogane. Checked the other housing cities, there were A LOT more. This was in Jenova.

Asked my friends in Gilgamesh, same thing there, though significantly less wards open in Shirogane.

So basically, if you didn't get a house... it's like, I mean... did you even log in after maintenance? .__.