I'm fine with people joining Shocker+. Just so long as they start off in an existing faction. At least until Shocker+ is properly off the ground. Shadow Eternity mook characters can come to Freddy's and wait for the impending corporate presentation to make their call.

As for Springtrap... Freddy's got a major overhaul with all the mooks coming in from the multiverse. Such changes include:

[list]
[*] New Animatronics (a collaboration between Wily Labs and Cyberdyne). The old ones were melted to slag due to being haunted. 
[*] Exorcism
[*] Shampood Carpets in the arcade
[*] New linoleum tiles in dining and kitchen areas
[*] Flight Simulator
[*] Ghostbusting
[*] New Arcade Cabinets
[*] Pizza Recipes from Florsheim's Count Vamp
[*] The Runes of Raggalor carved upon cosmic leylines passing through the establishment serve as one-way barriers between this world and the next, preventing the return of the dead but allowing their passing.
[/list]