Well no luck with the starter fluid. Fuel is officially ruled out.

I tried to rent a compression tester but the store said they rented it out yesterday, so I'm still waiting on that, though I don't think the issue is a head gasket. Oil looks great, and from the 2 or 3 times we have gotten it running, no smoke and no overheating (since I replaced the heater hose and thermostat housing).

If the compression checks out, I'm guessing the next step would be to check the CKP and CMP sensors? I'm not sure how to get ahold of an oscilloscope around here, I'm thinking it'll just be easier to buy two new sensors and replace them and see if that changes anything. If it doesn't, then aside from the ECM I'm damn near tapped out of ideas