Now, on to DLC Hype ....
I think ATs are, for the first season of DLC at least, off limits. Sorry Isaac! I was pushing for you!!! But, I'm willing to give them a second season chance. We aren't there yet, but we'll visit it then.
I think stickers aren't as strict as that. Geno I think could have a chance still. The fact that his image popped up showed their was communication with Square.
I think Microsoft is still a possibility, but I'm counting out Minecraft all together. This game tripled down on the fact that it is a Console game what all those stickers. Although Minecraft can port over to console, it doesn't do it well. It's clearly a PC game.
I think games that originated on PC could become characters, but only if their theme and feel is more of a console game. Undertale ... though I don't think it has enough history ... is an example of a PC game that is CLEARLY meant to be on a console. (It was inspired by Earthbound). I can easily see that game being represented.
I think Sora might be possible. Master Chief, Tails, Lloyd, Rayman, Heihachi, Banjo-Kazooie, Shantae ....
I think it's perfectly acceptable to look at more recent characters. We aren't limited to "two years ago" when the base roster was finalized.