I'd probably go with the orchid as well. I'll also say this. If you can find any tank-raised pseudos, purchase them. They might be a bit pricier, but they acclimate better, tend to be less aggressive, and they prevent pressure from collection for captivity. I tend to think that either one would be a decent fit for your tank. Also, just an FYI...PJ Cardinals tend to do better in groups. You might want to try adding another 2 or three of them to your tank, then adding the pseudochromis. Being that you'd add the pseudochromis last, I don't anticipate aggression problems, either.