One thing you can do for the mites is stick on some fly tape just above the soil line on the sides of the container they should get stuck to it. I have never personally tried it but I have raised all kinds of worms for aquarium fish over the years and have read a lot about this method. Another is cut back and or bury it under the surface and be sure to remove any left overs when you place new food in there. They don't harm anything but they are annoying I had them show up in red wiggler cultures in the past and just cut back the food and over time they slowly died off from lack of food but that doesn't always work.
Good luck and I need to get a culture going as well, I can't find any locally and the one time I bought them out of town they were all dead when I went to use them as I was in a hurry and didn't check the cup before I took off.