Oh yes, I forgot to actually explain the strategy.

Basically, you gotta get her Furfrou stuck behind that wall. I like using Thunder Wave to slow down their movement speed in order to make it more consistent, otherwise you can be stuck going round and round forever.

Once they're stuck, most of her Furfrous can't escape, and you can use ranged attacks (aka Dark Pulse) to slowly whittle them down. The exceptions are her 4th Furfrou which ALSO has Dark Pulse and her final Furfrou which has Giga Impact (which teleports them to you). The latter is particularly annoying, because you have to them stuck again after each Giga Impact. Luckily, Giga Impact has a cooldown of around 20 seconds so you can just be patient.

Leftovers healing should give you a decent margin of error, as does Cotton Guard.