You asked about the life cycle of flukes, and here's what Dr. Noga says in his book:
There are two modes of reproduction used by flukes, some lays eggs and some give birth to living young. From what I read, a microscope would be needed to determine which type is present, and a PhD in marine biology
Flukes cannot survive more than 2 weeks without a host (except if present as over-wintering eggs) --- Dr. Noga doesn't say what conditions are required for egg laying flukes to start laying over-wintering eggs, but probably a PhD comes in handy on that question too.
The egg layers have a free-swimming larvae stage that may attach to any new host, while the live birth flukes need contact between fish to be spread as they remain on the same host throughout the reproductive cycle.
If your non-angels don't have a problem yet, hopefully that is an indication that the flukes are species specific and won't spread further. We had a fluke attack on our Annularis Angel last July (it had stopped eating by the time we got it into a QT), and no other fish in the display tank ever came down with symptoms.
We also think that the fluke episode triggered a thyroid tumor in the Annularis ... but that's another story. We managed to keep the Annularis alive with tube feeding until its appetite returned, and it's now happily back in the display tank. If you're interested, full details here:
http://forum.marinedepot.com/Topic88860-10-1.aspx
Good luck with the flukes treatment ...