I think that's going to be more a personal preference thing. Myself, I'm a big picture kinda guy and I like lots of diversity in my worm bins and so far I've had no trouble with the bins... but then again I've not brought any bins back into the house since last summer. I did add compost pile leaves to my worm bins the first fall and winter (what wasn't frozen in place that is) and that introduced all sorts of interesting things to watch during the winter months but nothing dangerous to the bin or to my relationship with the wife. However I get it that bring in outside composting creatures (both big and small) can be a risky thing since many of us wouldn't really want to keep a compost pile in the house, even if it were only in the basement... as some of those things likely wouldn't stay confined to the bin and might like to live in other stuff in your house... for instance your houseplants for starters and what's in your cupboard and trashcans.

To each his/her own. I prefer to use grass, leaves , stems , garden cuttings , trimmings for my compost bins , not my worm bins, but have from time to time used leaves and such in my worm bins. I dont really have enough leaves where I live so I go to our town park and they pile those leaves up so easy to gather, thats just me.

I don't see much reason to bring my garden waste indoors to be composted; it's inconvenient to do it that way. My garden is a tiny city patch but I still usually find places to compost garden waste near where it's generated, chop and drop being the easiest. Bringing outdoor bugs inside would also be a hassle.

That said, it's pretty easy to get the worms to help you outside; once you have built up a good population in your indoor bin you will have plenty of extras to transfer outside to an outdoor worm bin or a cold composting pile. You can also take your hot compost and vermicompost it after it's been cooled down, which produces very fine grained castings (I think this is the usual method they use for commercially available worm castings).