I hope they don't try to include the Deadshot/Harley "romance". I would never have her be with any other guy than the Joker. If they want to separate her from Joker to expand on her character, that's fine, but I never liked the Deadshot/Harley hook up. If it were up to me, the best way to separate her from the Joker is to have her team up with Poison Ivy (regardless of if they make them a lesbian couple or not).
I'm not a shipper by any means, actually I like these movies better when there is no romance at all, just don't like the Deadshot/Harley thing. I also think Deadshot is a better character on his own.
Personally I'd keep her with the Joker for the entire DCU and have her team up with Ivy in certain situations.