Invert Fresh Water Dip / QT??

[ChelseaBidwell]

We just bought the below inverts, and I wanted to know if a FW dip is necessary/safe for them and if QT is necessary. If QT is necessary, about how long for these guys? They won't go in the same QT if they do go to QT, mainly because of the Arrow Crab.

2 Emerald Crabs
1 Fighting Conch
2 Peppermint Shrimp
1 Cleaner Shrimp
1 Brittle Sea Star
1 Blue Leg Hermit
1 Scarlet Reef Hermit

Thanks, guys!