As of now, I'm the only developer on the main version of the game, though I do have a translator working with me for the upcoming Spanish translation.
A night 1 Foxy jumpscare is rare, but possible, since his AI is activated halfway through the night. He probably got a lucky (or unlucky, depending on how you look at it...) set of movement opportunities.
Currently, there are no plans to demake any of the sequels, but I do have some future, non-GB/non-FNaF projects in mind.