bonus: this opens up for a TV show pilot of Harley and Ivy in the rainforest, with the villains-of-the-week being various flavors of people coming to clear-cut the forest for various reasons etc., so kind of like captain planet but is now vengeful lesbians
Harley is able to sit down and help with the mental troubles of the nearby town dealing with the effects of being part of that system, Ivy helps regrow the forest, they both take care to learn and respect the traditions/people already there
note: there can be an episode where batman gets a hint that they're where they are and comes on down to try and find them
however
this will be played completely for comedy as batgirl, robin, wonder woman, superman, etc. all totally see Harley and Ivy and all react with "y'all are doing good shit actually, we're going to keep fucking mum even if this means some very silly LOOK-A-THREE-HEADED-MONKEY behavior so we can keep batman from seeing you"