For the red one it is easy as they are very hardy. As for the blue one, I find that the key is to get an active one in the first place, Best if it is on the glass, not staying on the tank bottom and not moving.
I quarantine every thing wet but I read that starfish & sea urchins cannot carry the encysted stage of ich (Peter Burgess 1992), so I just acclimate it for about an hour. After that to be sure no water from other system gets into my display tank, I use 6 small containers filled with display tank water, then rinse through these 6 containers one by one before putting it into the DT.