IMO, you could do without the JWs who are guaranteed to screw up the already mixed up kids even further, don't you think?
Oh, come on. Guaranteed to screw up the kids? That's ridiculous. Many JW's have healthy and loving families that will do the kids a lot of good, even if the kids do come out of it thinking that Jesus picked the WTS as his "faithful and discreet slave" in 1919. Witnesses are generally moral people, and they certainly teach clean, wholesome living. I don't agree with most of the doctrines the JW's teach, and I agree that a few teachings and practices can be harmful. But for a kid who has been physically, emotionally and sexually abused to be placed into a stable home with a father and a mother and a moral structure can only be a good thing for the kid, even if they do have some wacky beliefs.
And as I've pointed out previously, there is not even a guarantee that the kids will buy into the whole JW thing. Two of my foster kids lived with us for 4 years each (a boy from age 10-14 and a girl from age 6-10), went to meetings with us all that time, and neither of them is a JW today. What the boy is, is a productive citizen with a job, a girlfriend who lives with him (OK, I'd like it better if they were married, but it's his life) and a child. I seriously doubt he'd have been that if he hadn't lived with us or someone like us. Probably, he'd have ended up in jail. He's also an avid reader (even though his IQ is below normal) - something he learned from me to love. He never needed a blood transfusion while he was with us, but if he had, he'd have gotten it - we had no power as foster parents to prevent it.
Now if the kid gets into a bad home - JW or not - where there is abuse and chaos, of course it would be harmful. But homes like that are generally screened out by the application process to become a foster parent, which is extensive, at least in Massachusetts. We had to fill out paperwork about an inch thick, endure several interviews, have everything from our credit to criminal records to medical records checked, have our entire house physically inspected, get references from friends, neighbors employers, etc. plus attend ten 3-hour training sessions (in which we and the other couples were being constantly evaluated as to our fitness to be foster parents). And if an abusive family was clever enough to get through all that and still be selected, guess what? It could happen with a non-JW family as easily as with JW's. JW's as a group are not abusive, any more than any other religious group. Most are not, some are. The abusive people of any religion (or, for that matter, of no religion) are the ones who should be (and generally are) screened out of being foster parents.