You have a leaking heater core. A control valve leak would leak in the engine compartment. The only possible leak inside the cabin is the heater core. There are no hoses, clamps, valves inside. Your symptoms are exactly what mine were: mist from the air vents, fogged windows, leak under passenger console. I tryed a couple of different stop leak products, they worked for about two weeks and then the leak became much worse. Sorry to tell you this, but that core is going to have to be replaced. By the parts online.
I don't have an answer for why you are not getting heat- I connected the heater hoses together at the firewall (bypassing the core) until I could get it replaced. Have you looked at the heater valve to see if it's opening? You could check it by applying vacuum. Good luck.