There's still the fact William will be doing stuff with Afton Robotics.
Mostly thinking of the Twisted animatronics, Funtime Freddy from Count the Ways, the tunnels from his location to houses. Pretty sure it was only two tunnels but still. Is also easy to forget that the illusion disks can also be put into lights. So be careful if William gives us light bulbs.
What are the chances he'll release springlocks himself too considering there was one at Circus Baby's? Actually looking back on the collab actions, William does intend to release Springlock suits for sale. To me that action reads as simply making the springlocks safer to use but could probably choose if we want to actually release them. So no matter what seems like the events revolving around those suits could still happen. Could work to make them safer to use though.
...Granted also opens up questions with the main points involving William and safer springlocks...
Also the Mimic...can't remember what was said about that.
The twisted animatronics I'm pretty sure we're literally just the Funtime animatronics with no paint on them.
As for the mimic, I didn't remember any of its backstory either so I just copied it from the wiki and here's what it said.
"It is an artificial intelligence from the 1980s meant to learn and mimic any human behavior it sees that turned aggressive after being assaulted by its creator Edwin Murray, before learning about and seeking to fully replicate William Afton's crimes. After being shut down and stopped for several decades, the Mimic1 program was brought back when a video game studio under Fazbear Entertainment scanned an old circuit board while making a VR game, causing him to return as a supernatural malware that manages to take control of a woman named Vanessa and turn her into his loyal, yet unwilling right hand. (Aka glitchtrap in the VR game help wanted.)"
"While Freddy Fazbear's Mega Pizzaplex was under construction, an endoskeleton containing the Mimic1 program was brought to the buried Freddy Fazbear's Pizza Place to help clean it up, but ended up killing everyone who dared enter it. The endoskeleton would later merge with the corpse of an unknown human, becoming "Burntrap" in a homage to Afton's Springtrap form."
"The Mimic would only gain more power after taking control of the Storyteller, a mechanical tree set up by Fazbear Entertainment chairman Mr. Burrows to generate stories that is controlled by the head of a white tiger animatronic, and he retains that form as the digital Tiger Rock. After being given control of the Glamrock Animatronics by Gregory, the Mimic essentially was in charge of the entire Pizzaplex."
"Once Gregory managed to redeem himself, free Vanessa from his control and escape the Pizzaplex, the Mimic started impersonating the boy to trick his friend, Cassie, into entering the Pizzaplex and freeing him. While he failed in killing Cassie, the Mimic was still set free and now has an escape route out of the Pizzaplex. Alongside this, he has taken the mantle of Helpi, an evil version of one of Fazbear Entertainment's mascots Helpy."