Hello, I've been visiting this forum because my brother (Deadeye) is on here. I'm from St. Louis, and I thought maybe I could be of some help...
I got flatworms in my 120 from some macro algea that I got (free of course) from another reefer here in the St. Louis area. I used "Flatworm eXit" per the directions and did not have any losses on any of my corals, inverts, or fish. However, I caution that you MUST follow the directions on the package EXACTLY, as flatworms will release a toxin when killed. You have to siphon the dead worms out ASAP and run heavy on the carbon, as well as making big water changes.
As far as the cyno goes, I've used "Red Slime Remover", and well as "Chemi-Clean" and I MUCH prefere ChemiClean over most of the other products. Again, if you follow the instuctions to the letter, you have little danger of losses.
With both problems at once, I think you'll have to be the judge on which "infection" needs to be cured first, as the treatments should probly not be done at the same time. In fact if it were me, I'd probably wait about a month in between to be sure.
So it's a matter of: Is the green slime (a form of the red stuff) smothering your corals, or are the flatworms?
If your 100% against any "chemical" style treatments, I've read some posts here on Reef Central about certain wrasses that are supposed to eat flatworms, though that's probly a bit "hit and miss".
Hope that helps in some way.