Thermostat housing went bad, luckily car was very near mechanic! However after fixing, codes are showing up and I am wondering if something major happened with the overheat or if it's perhaps some main fuse?

Codes
PO445 Evaporative emmission system purge control value circuit shorted
PO448 Evaporative emmission vent control circuit shorted
PO102 Mass or Volume Air Flow Circuit Low
PO340 Camshaft position Sensor A Circuit Bank 1 or single sensor
PO134. 135, 141, 155, 154, 161 O2 sensors no activity detected

MAF was replaced last year with a new Bosch and no problems since...

Much appreciated!

Sounds to me like one or more of the connectors didn't get plugged back in when the thermostat was being changed or they were checking for other issues. I just can't imagine all those different systems shorting out or failing individually even if they all got soaked with coolant...

That said, I'm sure some others will be able to provide more insight and other possibilities, but this where I'd start looking...make sure the O2 sensors are all correctly connected, the MAF is plugged in, etc...

did you overheat it?

Yes, it did overheat. The red light did turn on unfortunately!

make sure you don't have coolant leaks, most thermostats are replaced incorrectly because the vehicle overheated because of a coolant leak. not the thermostat. Look at the back of the head and the radiator and the front of the engine for coolant leaks.

But for the CEL light check the fuses on the engine just in case. I believe they use fuse number two. seen that many codes caused by a blown fuse. if it is blown then something is causing it to blow and then make sure all the connectors aren't screwed up and installed under stuff and rubbing on an engine or body part.