If you want one red and one blue.... I guess that rules out TT's.... since they are more orange/yellow in coloration. That said, I do have YKK's which are believed to have come from TT lineage (although no one knows exactly what, since the breeder took that secret to their grave?) and I have kept them in both Neo and Caridina parameters. The first group of YKK's I got from a breeder in California and they actually bred *FANTASTICALLY* in Neo parameters... at the time, I think it was play sand (for sure) and a mix of soft tap water (river water from lake fed by rain and snow melt) and hard tap water (basically well water - an aquifer). Due to unfortunate circumstances, that colony did not survive long. I later ended up getting another group of YKK's from a Florida breeder that were put into the same tank, but by this time, it was remineralized RO water, still with play sand. Not much breeding but the group was pretty young when I got them. I have since put them into Caridina parameters and have had a little more breeding, and now have some juvie shrimp.
So I guess that leaves you with the OEBT's, which I don't know how true they breed. This then means that you require a red shrimp.... which means PFR and Bloody Mary. I've never had PFR, but personally, I'd recommend Bloody Mary. Even the males are a brilliant red!
And the amount of culling may also depend on the line... I can't say who has the best line, but just something to consider.
All in all... do not purchase imports! Make sure you go with home bred shrimp!