As to "minors" -- I would say "NO". JWs and WT know that would legally be "neglect". But I do know of a couple kids tossed out on their 18th birthday. Of course, lots of folks send their 18-year old off to college in another state.
Bottom line is that the subject should not have to be debated. Shunning your family member because they are critical of the religion or have committed some dumb "sin" (as a teenager) is simply UNCHRISTIAN. (No natural affection?) It should NOT happen (exceptions for extreme cases, CSA, violence, etc).
A "Christian" religious group's leaders should not demand this and Christians should know better than to follow such demands and at the very least they should IGNORE such demands (if they aren't smart enough or brave enough to totally leave the group). Is there any question that any such high control religious group is a CULT?