Looks like it was a false alarm. I had re-installed the thermostat housing and put in a new gasket with a good amount of sealant all around yesterday before calling it a day. I just poured some water in the cooling system and there's no more fluid leak.

I still haven't been able to start the car but will be making an attempt tomorrow after I pick up some more antifreeze. Any last minute suggestions before I fire it up tomorrow?