Did you disconnect the footwell lighting again?
Do you have an aftermarket stereo?
Something is not wired correctly.
Maybe a car audio shop would have more experience with aftermarket lights than a Chevy service center. Someone might spot it in 10 minutes. A second set of eyes should always be your first step
The doors won't lock if the car thinks the key is in the ignition. That's a clue. Something is telling the car there is power on. The FOB won't work.
There are two ways I know of to lock the car with a key in the ignition. At least until you have your Camaro repaired.
1. Argue with the button on the door. Press it hard and hold it. It gives up after three tries. It's cool the engineers thought of this
2. Close the driver's door, enter through the passenger door and leave it open. Hit the lock button on the dash. Exit and close the door.
You will need to use the key in the door for reentry as the FOB will remain disabled.