I'm not certain we can conclude that. For all we know everything is the same, they just clicked the 3D button instead of the "isometric" one
Yes we can. The dev themselves has stated that the long wait was because "The game is currently undergoing total redevelopment from scratch"
Redevelopment. From scratch. Doesn't sound like a press to 3D button to me. And the worst part of this is their reason was so they can add more content and give the game a real story. This is bullshit.....in a fashion. They might truly think this for all we know but the truth of the matter is this was an out-of-the-blue ADHD moment that costs them 6 months of ACTUALLY providing content and story.
Remember, the story mode had changed concept before from the actual interesting puzzle-like version of FNAF to FNAF just with a 2D movable avatar. And they totally took out survival mode which was the only way to unlock scenes in ver 1.6/1.7, so it seems their development is more reliant on the whims they have that day rather than any real thought out process.
Something avoidable if they had a project manager.