^ Somehow I doubt that a show like The Flash is going to ascribe to the same time travel mechanics as the Back to the Future films, which had some of the most honestly wonky rules about time travel that I've ever seen (that's not to say that the films are bad, because they're not).
BTTF was nowhere near the first or only work of fiction to show a time traveler meeting his or her past self. That trope was old before Robert Zemeckis was even born. Robert A. Heinlein used it repeatedly, notably in 1941's "By His Bootstraps" and 1959's "--All You Zombies--". And so have plenty of other authors since.
Barry can't have Felicity & Iris!?!? Go for Iris!
Why? Okay, she's marginally hotter, but nowhere near as smart, funny, thoughtful, supportive, and resourceful. If you want someone to put up on a pedestal and stare at, then Iris would work. But if you want a life partner who'll enrich your existence, then Felicity's by far the better prospect. (Assuming, of course, that either lady is interested. But there again, Felicity comes out ahead, because she's already interested in Barry. If Iris hasn't thought about him as a romantic prospect in all this time, why expect that to change?)
Oh, speaking of life partners, I liked the casual way in which Captain Singh mentioned his boyfriend. I don't recall if we've had a gay male recurring character in this universe yet -- the only LGBT characters I can think of are Sarah and Nyssa.