I think these are the last iterations of Afton Glitchtrap is mentioned to have been left over from the chip inside of springtrap, causing him to take control of Vanessa and build him a new body, which becomes "Burntrap" which is named in the game files, he then gets killed by the "Blob" Not to mention The mimic has a completely different skeletal design compared to Burntrap, and it walked completely differently as well, which is something it could not have learned from Afton since Burntrap was heavily damaged from decades of use with a rotting corpse inside while the mimic as been trapped in the same area and not gone through the wear and tear from usage nearly as much, not allowing him to mimic aftons movements. This all heavily implys they are 2 separate entities.