If the thermostat is jammed on, then you need to replace it. CHeap, easy, and clean. No biggie.
How much does an intake camshaft position sensor cost? I don't even know if it is hard to replce
I don't want to make any costly asumptions here. I'll let somebody else chime in on that one.
The third code confuses me a little bit. I am not sure, but it may be a lose, shorted, or boken connection somewhere. I don't know if this is related to the coolant temperature snesor, which plugs into the side of the radiator (check that connection).
What does the bavauto manual say about the latter two codes?
DO you have a Bentley repair manual? It is a must-have for these cars.