I got those same exact codes when my idiot cousin put an additive in the oil, I think it was called something like RESTORE. About a mile of driving later, engine would chug and stall and I would get the SES and REP lights. I just changed the oil and disconnected the battery and all is fine now. If you're using a good oil and not those cheap $5 additives, then read below.
Your timing chain is fine. There's people on this forum that have well over 200k miles and did not mention anything about a timing chain being replaced simply because they don't need to be. Changing the camshaft actuator and sensor was something i would've done too. If anything, you may just need a CASE relearn from the dealer to fix everything up.
There is a how-to on the site for replacing the camshaft actuator solenoid. Its not that hard and takes about 30 minutes. You need to take off the serp belt and get to the power steering pump and take that off as well. That way you'll have a lot more clearence for the actuator.
2002 Oldsmobile Bravada: 4.2L I6 w/ G80 Locker, AWD, TBSS springs, HD bilsteins, 6000k HIDs, Mobil1, Iridium Plugs