I would use CC in the small tanks, I have'nt had luck with sand in small tanks. NO lighting would be fine as long as there is no photosynthetic organisms in there I would think. As for a filter, how about a biowheel 330 with no wheels or carbon? A timer for your lights, and a food timer would solve your out of town problems. Why not just stick with one shrimp, like a mantis? You wouldn't have to worry about compatibility issues then!
