Just liquid ferts should be fine for a low-med light tank. If you want, you can also use root tabs- which is fertilizer you stick in the gravel by the roots of the plant. Your fertilizer regimen should really depend on the type of plants you have, as some draw heavily from the roots whereas other depend mostly on nutrients in the water.
Ghost shrimp and cherry shrimp will not interbreed. In fact, ghost shrimp can't reproduce at all in the aquarium, as their larvae require at least brackish, if not fully marine conditions in order to survive. Cherry shrimp on the other hand, breed quite readily in the aquarium. Their young do not have a planktonic stage and are born as mini versions of the adults. Ghost shrimp don't particularly eat algae, but the cherry shrimp are great at it!