My worm "habitat" is in my carport. Although there *are* flies in the carport, they stay up in the roof area. Where the worm habitat is, there are no flies, even though statistically there should be some.
And no odor, even when I lift up the lid to feed my little invertebrate workers.
Because it's outdoors, though, a few undesireable critters (a couple of slugs, and earwigs) have found their way into the worms' home. despise slugs, despise earwigs
But Mary Appelhof, pioneer of vermicomposting and author of Worms Eat My Garbage, experimented over the years with keeping worms in the kitchen: under the sink, near the traffic paths, etc., and never experienced odor problems or "invader" problems in the house. She also enlisted the academic and gardening communities in her town to perform both controlled and open experiments/observations, and the verdict was uniformly positive: worms were fine in the house.
Maybe you'd like to pick up a copy of her book second-hand? Her tone of voice (in writing, of course; that's all I have to go on) was very warm, friendly, and down-to-earth.
Worms Eat My Garbage (2nd ed., 1997), Mary Appelhof, ISBN 978-0-9778045-1-1, pub. by Flowerfield Enterprises, LLC, 10332 Shaver Road, Kalamazoo, MI 49024