Poor little guy! I'm sure he's had a very rough trip. Thanks for helping him out.
For something of that size, I would recommend getting Springtails or Drosophila melanogaster fruit flies. Ed's Fly Meat is an online store that I purchase mine from, and they are very reasonable in price and helpful.
Buying small potted plants requires a bit of careful practice. When I buy them, I wash the leaves and plant material off as much as possible, rinse them a few times afterwards and also change out as much soil as I can. That makes it less likely that chemicals are left behind that can harm them. You can also buy plants from growers that specifically grow plants for these situations.
You can substitute real plants for fake terrarium plants and plastic-based fake foliage until you have some good stock growing. Rinsing is still a good idea. For misting, I recommend distilled water. It's safer and also doesn't leave hard water stains!