Those are a lot of setting pictures O.o Will take a while to shift through xD

Fantasy World:
Something together would be cool! *thinks* No wands, no... The energy/chi would be interesting - especially if it was their own, then they can only 'draw'/use so many. Or we could do something similar to Aons in Elantris by Brandon Sanderson (doubt you've read it but...) where basically they're drawn in the air and kind of hang their, doing whatever effect. But energy/chi would be cool. Yeah I think those four images would be cool - the classical elements (I would say earth instead of rock but that's just me). 

Sci-fi World:
I agree with sleek and gritty ;) (BTW Guardians of the Galaxy is amazing)

Yeah, no robots. I mean I know its in a lot of sci-fi but it just goes against everything I know about AI... I mean obviously its not in the modern world but still. I think maybe technological body parts, though? Like if someone loses a hand they can get a new one that works like a normal one. Hover boards are cool (as long as we don't go too down the Back to the Future 2 route xP) and limited teleportation - either it only teleports short distances or there are certain stations and it takes up a lot of space so it isn't widely available and limited as to where you can go? Definitely laser tech... Cool computers? I mean any computers in that world are going to be super fast with super high RAM. I think there should be 3D computers... Okay, sorry. Going off topic a bit. Computers aren't important really.

Modern World:
All sounds good when it comes to the mirror. I should add to it, but my brain is a bit dead at the moment. Apologies. 

Yeah I agree with that kind of prophecy, sounds simple enough. Anything more might just get a little bit confusing and hard to keep track of.

I like the idea of it getting messed up in both the modern and fantasy world, in different ways, and the sci-fi world getting it right. It would certainly be interesting for when the pairs meet and the possibility of characters becoming more 'evil' per se/ becoming anti-heroes. Yeah sounds like a brilliant idea

(I'm sorry I'm being terrible and contributing, I'm trying honestly I'm just tired at the moment and its one of my down moments mentally)