The p0420/430 codes mean your catalytic converters are no longer cleaning up the exhaust at the level they're expected to. An exhaust leak somewhere after the upstream O2 but before the cat converter itself can supposedly cause this code, too, but since you have this code on both banks, that's probably not what's happening.
The cam sensor code may be related to your difficult start situation. The sensor should be checked to make sure it's getting power, ground and that it's outputting its 5V signal. You can do this with a capable multimeter, but it's best to do with a scope. Comparing both cam and crank sensor output signal to each other on a scope can provide even more in-depth analysis on whether the former is working correctly as well.