Never played Dota2 but I've always wanted some sort of customization mode. I don't think that its the huge mode they're keeping a secret though.

They did the same thing in Killer Instinct. I doubt it though since the variations looking different and the fact that MK gives at least 1 alt per character.

Ideally yes, since you could have unique characters not only in variation choice but in aesthetic, but it probably won't happen.

I actually want fighting games to away from customization. It so rarely looks good.