TL;DR version at bottom.

So a while ago I ordered the Mazmart thermostat and water pump, recently got around to installing them myself (old thermostat got stuck), about two or three weeks ago. Anyways put it on, everything is good, highway cruise temps are consistently between 190-210. Two week later, disaster.

I'm driving along a parkway, just cruising, when I look over at my COBB and see 248F on the coolant... HOLY ****!!! I immediately pop the car into neutral and shut it off, coasting towards a business side street. I then realize that my COBB won't monitor with the car off (right?) or operate the fans, so I turn the key back to ON. (Not engine on, key position on, that would just be idiotic.) Still monitoring, still coasting, I see the temps rise... 250, 252, 254. then they start going back down, along with my heartbeat.

Once I coast as far as I could on the side of the road, I ended up stopping in a right-turn lane off a busy street. I then pop the hood, and notice tiny black fibers everywhere. Looking further I see my water pump/alternator belt is gone, as in it doesn't exist anymore. Well poop. I call my insurance, and they send a flatbed out to tow me home.

Getting home, they put my car *** first into the garage (Tuesday), because of how it was loaded. Today, I know I'll have to turn it around to let it idle without suffocating, so I drive it out down my driveway, around the cul-de-sac, and back face first into my garage the way it should be, carefully watching temps the whole time. It drives just fine the whole time. It's not too hot so I get to work, replacing the WP/Alt belt *and* the AC drive belt (why not, it's cheap, and I'm already there). I fill the coolant reservoir back up, some leaks out of the radiator (it's always had a small leak (only) when cold), but it only enough water to barely fill a shot glass.

Anyways, I get back in my car, plug in my COBB to watch the coolant temp, and start it up. it cranks and idles just fine, like it always has, and continues to do so for several minutes while it's warming up. I just the belts to make sure they're rotating correctly, and they seem to be doing so. Going back between looking at my tuner and looking and the belts, I see the temps get closer and closer to 170~ish, the point at when the new thermostat starts opening.

Right around the time the COBB reads ~170 there's smoke appearing from my engine bay (white, but not thick), more so from the front than the rear. I immediately jump in the driver's seat and turn off the whole thing. Researching, I find my belts may be smoking if a pulley is caught. I readjust them (supposed to after idling anyways), and start the car again.

It cranks, chokes, chokes... dies. Crank it again, chokes, chokes, dies... Crank once more! Chokes, fights, idles high, than settles down at normal idle speed, with no hiccups for a bit. I see that the pulleys are all spinning good, so let the car run. Coolant reaches back up to ~170, smokes billows from beneath the airbox and battery, I shut it off.

I figure I'd let it cool off, then actively look for the smoke source. The way I see it, the engine is either already f**ked or it's not, and idling at 170F isn't going to change anything! 10 mins later, I start it, and wait by the engine bay. It cranks and idles just fine after I get the excess fuel out of there (gas pedal + ignition). Smoke comes up from under the airbox again. I pull out a flash light; it's not the belts, or the engine block. It smells sweetish, so I'm guessing coolant. I get down and look under the car and see smoke coming *down* from behind the radiator, but at a faster rate, like it's being blown out by the fans. It starts idling a bit rough so I turned it off.
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TL;DR version:
Thermostat got stuck, replaced it and water pump (mazmart version). Water pump belt snaps two weeks later, car is towed home. Install new belts, re-fill coolant reservoir, tiny tiny leak, but it's normal. Car cranks and idles just fine first time, then smokes. Shut down, re-adjust belts, try again. Rough idle after cold stop/start, still smokes. I clear the gas out of the rotor chambers, it cranks and idles just fine. Find out the smoke is coming from the radiator, after water temp reaches ~170 (when the aftermarket thermostat opens and allows circulation). Car is shut down.

So what do you guys think? Is my engine done? Is it the radiator/hoses? Is it something else? Any comments, ideas, or general input would be greatly appreciated! This is my first/only car, I love her to death and would do anything to see her well again.

Relevant info: '04 MT w/ 126,000 miles/ good condition ignition/ 2K on current 10W30 regular oil/ 1oz per gallon premix/ straight pipe/ Racing Beat ram intake/ COBB w/ MM base tune (v0)/ Always ran like a dream since purchase @114K miles. No knowledge of previous owner maintenance.