What size is your tank? I would also suggest you find out what your albino bottom feeders actually are before you add anything else in case they are not compatible. I suspect they might be albino corys but that's just a wild guess.
YES!!! You should definitely have a shoal of 6+ Serpae tetra, 10 is ideal Your albino bottom feeders are probably Corydoras catfish, as Lunar Jetman says, and all these fish are compatible. The Serpae's are likely to out-compete the Rosy Barbs for food though, and could scare them at feeding time, but they should be fine!
What size tank do you have though?