Re: 1). As far as I know, all the four cylinder engines will not start with a faulty cam sensor, (the 5 cyl diesel will). So, if the cam sensor code returns after clearing and is therefore genuine, it would appear that you have a fault that occurs during initial cranking, and then clears. After twenty minutes running without a recurrence the ecu lets you drive normally. Something like that?
Is your battery weak? If the voltage goes too low during starter engagement, the ecu may not be able to maintain the regulated supply to the sensors. If the crank sensor recovers before the cam sensor, the ecu will see a fault. I confess this is mostly theory, but if you have any doubts about your battery it may be worth trying a jump start from a running car.
Jump starts can damage the airbag ecu. Pulling its fuse beforehand should improve its chances.