Group quarantine question: FW bath one at a time?

[SteveG_inDC]

Looking for some advice specific to this quarantine

I have 6 tank-raised banggai cardinalfish in quarantine right now. After 5 days, they seem to look healthy, no signs of aggression or disease. They are swimming normally (for this species) and eating. They actively seek food of all kinds, but they spit out pellets, flakes, and Rod's food whether or not they are soaked in garlic. They accept baby brine and frozen PE mysids.

I have not treated with medications, but they were in the LFS for at least two weeks with Cupramine at 0.5 and salinity at 1.017. I've kept them in an unmedicated 30g tank with salinity at 1.019.

My questions:

1. Should I do a freshwater dip? I'm thinking yes, but can I do them all at once? If not do I have to collect them and keep in a waiting container with saltwater (waiting room) because otherwise I don't know how you keep track of which ones I've done and which ones are waiting!
2. This gets to my second question, which is that if they are identical (to my eyes) then how do I observe their individual progress? At each feeding it seems like there is a leader (ok, I think I've identified him/her) and others seem to be waiting their turn with one shy one whose swimming pattern is slightly different (hanging back a bit). How can I tell if it's the same order every time? In particular I want to know if I should worry about the shy one. I can't get them to wear their nametags Seriously, I suspect they will start to look different over time as some fatten up more than others, but not sure if I can or should do something like add a tank separator (I have one ready).
3. Given that these guys are going through a second quarantine, should I just FW dip, watch for flukes in the bathwater, and after the two week mark in my QT move them to DT? This seems to be best-case scenario with them being tank-raised and having been prophylactically copper treated at the LFS, assuming they come out of the FW dip clean.

Thanks in advance!

 

[SteveG_inDC]

Bump.
should I put in a tank divider FW dip the fish one at a time? (Divider is so I can tell which ones I’ve dipped. Put undipped on one side and move to other after dipping)