I think you will face problems of ideology, but I don't see why it shouldn't be do-able: if you can do ABA in a mainstream classroom, then it ought to be possible in the relative calm of a unit. The problem will be prejudice against ABA from the staff, who have probably been told for years that ABA is awful. But it just takes one feisty mum to show them in real life that it is fun and effective and doesn't compete with their own ideas. But you may have to compromise to some of their ideas too, show willing. I say go for it, softly softly at first
"Positive behaviour support" is all the rage (it's just ordinary ABA) Ordinary synthetic phonics is usually heavily ABA-flavoured example PECS -especially done by the Pyramid people - is pure ABA Sticker charts, a dip in the 'treat' box, even the awful Golden Time - they're ABA when done competently (though often woefully mishandled) Flashcards done as SAfMEDs are ABA
Ask how they would teach a reluctant child to use the loo independently. Don't worry if they fail to mention the technical terms- it doesn't matter whether anyone's told them the concepts are called association, backward chaining, reinforcement, shaping, extinction etc. just ask exactly what they did the last time this situation arose. That'll tell you if they'll 'get' ABA.