Don't add anything till there is no ammonia or nitrite, and you've done a large water change to remove nitrate.
Meanwhile, you really do not need a "clean up crew". diatoms will go away as fast as they came, and nuisance algae comes with excess nutrients. keep your feeding reasonable and your bio load reasonable as well, and you'll be fine. Add crabs, snails, and shrimp as you want then, and not as you need them. Remember, everything you add will need to be fed.