BB's significance in the FNAF2 movie is more then it seems
I think the biggest clue here is realizing that the loudspeaker feedback that starts when BB's eyes start glowing sounds rather like a scream? A warped, jumpscare-noise-like scream, but still, a scream to be sure!
So let’s dive into this, not just the scream, but everything else.
First off, notice that Balloon Boy does not attack the spectral scoopers along with the toys.
If Charlotte is controlling him, why wouldn’t she? Being small isn’t an excuse. She had a whole army of tiny puppet plushies attack that one guy. And BB clearly has no problem with being in the water, so that’s not it.
He is not a toy. We see that in the sequence where Mike boots up the computer. Toy Chica, Mangle, Toy Freddy and Toy Bonnie are there, but not BB.
But he’s not a prototype either, because he was active in the river section, before the withereds were shown waking up.
So WHO is he?
And why did he not attack the spectral scoopers along with The Marionette and The Toys?
His small size does not explain it. As Charlie had several smaller puppet dolls mob one of the scoopers. If she were the one controlling BB, she could’ve had him attack along with the puppet plushes.
But then Mike shows up.
But when Mike is there? BB immediately shows up.
And though Mike and Vannessa assume he’s attacking and flee in fear, the reality is: BB, per usual, never attacks.
With the long hallway to Mike’s room, why does BB take all that time laughing in the dark, when, earlier, in the stream, he dashed towards Mike and Vannessa without hesitation?
Could it be because he saw that a quick approach had frightened them and wanted to take his time?
He’s so shy when he comes into the office, peering over Mike’s computer.
And then, when he has Mike's attention, the result sounds like a scream: a distorted scream, but still a scream, that wouldn’t sound too out of place in a jumpscare in one one of the mainline games.
When Mike tears BB’s head off, BB doesn’t move and doesn’t struggle or even try to run, even as Mike visibly has to slowly wrench the head off BB’s neck.
It’s like he’s in a trance. Potentially meaning that he was never intending to harm or distract Mike.
I believe that this was Garret again. If Charlotte can compare little smaller versions of the puppet, why can’t all the BBs have a connection to Garret?
If he is connected to Garret and the little BB statue from the first movie, he reliving Afton’s murder of Garret or putting all his energy into trying to send Mike a message?
The scream in the loudspeaker wasn’t intended to distract Mike, but rather it was an attempt to get Mike to notice him again. Heck, the little BB from the first movie could have been spiritually piloting this BB in the same way The Puppet piloted Toy Chica for all we know.
And, crucially, BB’s eyes do NOT stop glowing after Mike rips the head off, even if he were simply a robot-following-commands that should have severed the connection.
Almost like he’s haunted.
Incidentally, it’s just like the first movie. When the vandals began tearing up Freddy’s, the BB statue did not participate in the attack. Here, the spectral scoopers are the first group of victims, and the toys attack, but BB doesn’t participate.
But Mike causes him to come running - quite literally based on how he initially hurries over in the river scene.
Under the BB Garret theory maybe this will cause Garret to become unhappy or afraid of Mike in the third movie. If they do happiest day in the FNAF3 movie, I’m looking forward to see how they show BB’s involvement.
tl;dr: BB's eyes glowing is supernatural and the noise that comes from the loudspeakers sounds like a scream.