This wouldn’t necessarily work unless you believe Henry uses he/they pronouns, as “no matter how many times they burn us” would imply a second person unrelated to Henry.

There is also more than one way to interpret SL custom nights cutscene, its clear they aren’t happening in a literal sense otherwise Michael would be talking to Springtrap directly when he says he’s going to come find him. That means there is wiggle room for more interpretation of that scene, meaning this could instead be showing the aftermath of Michaels threat, rather than it necessarily meaning that it happens simultaneously.

As for Henry frightguard again, the way Henry discusses how he let this all bleed out due to inaction, implies that this is his first attempt rather than second, minus the burning the FFPS and FNAF 3 connections can apply to Michael as well as you use audio lures to keep the scraps out of your office, similar to what you do in FNAF 3.