[NicolasOL]

My only problem with this is that even if it works and these critters are able to control ferals, what then? After the feral population drops, wouldn't native fauna come under threat of predation by these introductions?

The experience quoted in the article is no, that is not the outcome. There remains enough cats and foxes (both quick breeders) to keep the top predators fed without placing pressure on the smaller native animals.