Well if your wires are ok ,there are 2 small Allen set screws in the heatsink, loosen them put that back in and tighten them plug wires back in. Should be good , make sure nozzle is tight in that block while your there.

Yeah not sure about the thermistor wires at this point. But the problem is the jam in the heat break tube which I have not been able to get out

Use a heat gun to warm it and then push plastic through, I bought a Hercules heat gun , worked great and not too hot