There is obviously a connection between these two scenes. Golden Freddy on one end. On the other, 4 kids with masks for Freddy's band. The rest of the buildings also match, though you can't see it here.
Interpretations of this parallel usually imply that the rightmost kid in Happiest Day is the Bite Victim. MatPat is convinced that this is a narrative callback, characters reuniting to give BV the birthday he'd never had. It's easy to see the appeal of these kinds of interpretations.
The intuitive problem with this, in my opinion, is just that it'd be absurd for the 5 kids in Happiest Day to not be the 5 missing children. BV didn't even exist at the time of FNaF3, and I don't think this connection is obscure enough to be the retcon. It's always been 5 kids, lured back and killed, possessing Freddy, Bonnie, Chica, Foxy, and Golden Freddy. It's more or less the main point of the story, and it's been reiterated over and over. The first 4 children wear the animatronic masks, representing their haunting of the 4 animatronics. The final child wears a Golden Freddy mask. It's hard to argue they aren't the child who possesses Golden Freddy.
So, here's a slightly closer analysis of this parallel. There's the 5 masked kids and Golden Freddy, yes. But let's not forget, Happiest Day also features the player character, the Puppet, standing right there between Golden Freddy and everyone else. Now, look where BV (the player character) is positioned during the bite. Remember how strongly BV's design relates to the Puppet, with the black and white stripes and constant tear tracks.
BV isn't parallel to Golden Freddy, that's Fredbear's role. BV is parallel to the Puppet.
The point of this connection is not to relate BV to Golden Freddy (Or the Puppet, for that matter). Rather, it's just one out of a series of connections which imply that the cake minigames are BV's memories.