I've recently suddenly got convinced of CharliePostMCI. (But not Charlie87)
My reasoning is the FNaF 2 minigames. In most of the FNaF 2 minigames, there's a phrase being spelled, like "SAVE HIM," "HELP THEM," and "SAVE THEM." The only minigame where this doesn't occur is Foxy Go Go Go, the minigame that shows the MCI kids' corpses. And all the minigames where a phrase is being spelled have the Puppet be present in some way; "SAVE HIM" shows the Puppet's death, "HELP THEM" shows the Puppet giving life to the MCI kids, and "SAVE THEM" shows the Puppet moving around the FNaF 2 location. But in Foxy Go Go Go, it's just buzzing; Probably because the Puppet isn't present, which could be because Charlie hasn't died yet.
Now, despite that, I don't believe Charlie87; Because I find the idea of Charlie dying in the same week as the DCI to be incredibly weird and convoluted, and also because I believe GGGLBodies, the theory that Give Gifts Give Life is the Puppet showing the MCI kids their bodies, and if Charlie died in 1987, she probably wouldn't be able to because Fazbear Entertainment disposed of the bodies, as we clearly don't see the corpses in the Withereds in gameplay.