Well... for anyone who may be interested, I found the solution to all of my troubles. About a month ago, I went out to get a new tank since I finally decided there had to be something wrong with my 55 gallon. I opted for a 95 gallon wave (bigger tank to help ease anything i may mess up). I got it all setup, plumbed it the same way (except for one thing), got the fish and anemones in, and they've all been doing great ever since.
The one thing I changed is something I would have never thought of... I got this new tank from my local ma' and pa' fish store. They tried to sell me all they're plumbing parts, but I politely told them I could get PVC, vinyl tubing, and all that stuff cheaper at lowes and they were pretty quick to agree, but they were VERY adamant about me buying a check valve (for the return line) from them. They mentioned that they used lowes check valves on their plumbing in the past and had a lot of troubles with dying fish when they did that. Apparently the lowes check valves have a metal flap in the middle thats known to degrade and leech elements into the water when you first put it in. For the typical lowes customer application, thats not a problem at all, but for an aquarium application, thats a death sentence. So I bought the plastic check valve (flapper, connectors, and all) from my LFS, set everything up excatly the way I had it before after thoroughly rinsing it off, and now everything is going great!
It's been about a month now and there hasn't been one fish/anemone to die or even look so much as stressed. Everyone is playing hapilly and I think my two clowns may be close to mating. I bought them separately and they'd never go near each other or in an anemone before, but now they share one happy anemone and kind of chase each other around the tank and do this funny little dance.
Needless to say, I'm a little pissed at lowes for having metal components in what's labeled as an all plastic check valve, but I'm stoked at the same time cause everything is doing so well all of the sudden!