Having duplicates from the other world could be very interesting for Flash. I have a feeling that the Killer Frost we see first won't necessarily be the Caitlyn we're used to.
I've also got theories on Cisco's inspiration for the Flash signal being something from the other world as well.
Every child, woman or man
Opinion don't matter, stick to your plan
If they judge, still don't budge
Don't give an inch, don't give a nudge
Life's a bitch, leave you battered and bent
Lose or win, gotta hold up your chin