Without knowing the shrimps genetics, it's kind of hard to determine what the offspring will look like.
Blood Mary x Painted Fire Red results in red offspring. I do not know how the offspring compare to either parent's coloration.
To that extent, I would assume that breeding Blue Dreams to Blue Velvets may also result in blue offspring.
However, when it comes to mixing separate colors.... it's really a crapshoot. If both mutations are recessive, and neither one is co-dominant, then offspring should, in theory, be brown. There's a breeder who keeps a mixed tank of Neo's and says he hardly ever gets any brown offspring. He has gotten some unique colorations, too. This includes purple, yellow rili with red spots, and others. Tank does have blue, red, yellow, orange and rili shrimp in it. Possibly even blue pearl and snowballs?
It's interesting to see the colors!