The Flash, Firestorm, and Arrow vs Reverse Flash?

     The first official crossover between The Flash and Arrow was unbelievably successful, with more crossovers on the way and a new crossover spin-off show in the works. If these new set photos hold any weight, then we might have our most epic crossover yet coming soon.
     New set photos from The Flash show Barry, Firestorm, and the Arrow standing side by side, with Harrison Wells/Eobard Thawne standing in front of them with his Reverse-Flash suit on. We have arguably 3 of the most popular and important heroes on the CW against probably the most powerful villain in this universe.

     So here are some of the better ones from the bunch, but the link is up there if you want to see them all. Everyone seems to be in their usual attire (Firestorm really needs a real costume) except Oliver, who is rocking some League of Assassins gear. Before we assume that he accepts Ra's al Ghul's offer, let's take a step back...

     The Flash has been dealing with time-travel as of late, and they will obviously continue to explore its implications. We know that Barry can time-travel, and we can assume that Reverse-Flash has/had the ability to. I say this because we still do not know his endgame, but he obviously is working to get Barry to go faster, he wants to go home, and he has super-speed. So, with that in mind he probably can't do it at this time for reasons unknown. Maybe Barry has really messed with time, and these set photos show them in some alternate timeline/dimension where Oliver accepted Ra's al Ghul's offer because of the Flash's tampering with the timeline.

     But I doubt this. The other 3 characters are in their normal costumes, and the 3 heroes are facing the one villain. So they aren't on different sides if this is some other timeline. Plus, if this is some timeline where Oliver is Ra's al Ghul, wouldn't this have bigger implications for this universe? Who's to say Firestorm isn't bad? In some other universe, could these people have different costumes and be on different sides? This is just speculation, but I'm trying to take in all the possibilities.

     Maybe Oliver needed a spare costume because his got damaged or something. I think I am one of the few people hoping Oliver become the leader of the League; but why I wish that is another article entirely. I'd love for some people to comment with their thoughts!