Why is it overheating when the gauge reads different and fans not working

No i haven't purged the air, could that be the reason for overheating? Coolant not hitting the sending units? Or if the radiator was backed up cause the piece's of plastic that broke off the outlet were never found?

I don't see it being a restriction. I see it being an air pocket. If you have opened the cooling system without any "burping" of air after the repair, you're going to get boiling over as the air comes to the surface. You should have a tool for this at best - to prevent scalding hot coolant burning you, and at worst, you run it, and release the cap to purge air periodically, adding coolant as needed. This is not for a novice, because serious injury can occur. Not saying this is what's wrong, but saying it needs to be eliminated as a variable.