Oh yeah, sounds like mites. Leaves and grass, those will bring them in. Harmless though.

He's a page on lots of the lovely creatures you might now be discovering (good pics) :). Mites and springtails being very common but no worries as they don't leave the bin. Springtails might try... but die in the dry air almost instantly.

http://www.redwormcomposting.com/category/worm-bin-creatures/

I've got mites in mine too. If I use damp newspaper as a cover under the lid and change it out frequently, I can thin them out pretty well, but the worms don't care. A house plant fanatic friend of mine did suggest that before I used the compost I might heat it to kill them off. Apparently some mites can be detrimental to plants.

I believe the fruit flies are just part of the joys of worm farming. I've learned to live with the occasional swarming but notice that they seem quite happy just hanging out inside the bin and don't cause much concern if they are not disturbed.

For the most part, you are going to see alot of little critters other than worms in your bin. Some of them like the snails, I would make the attempt to reduce....(you probably can;t eliminate them). Others, just deal with them unless they begin to create a problem.\

Alot of times these critters are the result of exposing your bin to outside bugs. Pot worms, fruit flies etc are endemic. You are going to see them in any worm soil. The numbers will vary and may be hardly noticeable..

Some of the others are a direct result of you either using bedding/food that has been contaminated or you raising your worms outdoors where anything can enter the bin.

Those little white eggs sound like more fruit flies. They reproduce rapidly. People have always claimed (and I have been guilty of repeating that claim) they don't burrow. That's crap. They burrow just fine if the material is somewhat loose. They'll burrow as deep as a the second tray down in a worm factory and use the screen bottom to lay the eggs in. I learned that from experience.