Unfortunately, flame and "electric" scallops are poor additions to a tank and rarely survive more than a year. Most starve to death, even if "spot fed." This takes time, so success under a year is not a good indication of how well they will do. In some tanks they do live longer but this is not the norm, I am afraid. Furthermore, they will move where they want and should be left wherever they go. Trying to remove them can damage them. So don't be surprised if they end up behind your rocks.
What kind of star is it? All brittlestars should be spot fed. The green is a known predator, and MAY pose a threat to shrimp and small fish, though not for sure. I would talk about acclimation, but it is probably too late.