User blog comment:ImperiexSeed/Who will Zoom be?/@comment-2111740-20150811224606

My guess is that they would go with an alternate or future Barry. I think it is indicated by the blue electricity or whatever it is from the trailer. The Flash Imperiex has as his profile pic, in the comics is a future Barry so it makes sense.

On the other hand, they could go with Eddie as well, or at least a version of him. They could combine him with Cobalt Blue but make him a speedster instead.