Hi Treacle,
Sorry I didn't get on last night, my husband came in and commandeered the PC!
Ok, your tank is is actually only 26 gallons, which unfortunately isn't big enough for your plec. Angels like a tall tank, so if you're tank is 20" high you could get away with a couple of Angel fish.
Anyway, the best thing to do now is probably to post a message on the tropical chat board asking for stocking ideas. I know you're not going to like this but I would return the plec and the fighter to your lfs, and start from scratch. Bearing in mind mollies prefer brackish (slightly salty) conditions, you might want to think about that too. However in my opinion Mollies are the most friendly, gorgeous fish, I just love them! So much so I bought a tank specifically for them.
I think a couple of things have led to the deaths of your fish. One, the tank probably wasn't cycled and although they first fish survived this, it severely comprimised their immune systems. When more fish starting arriving, this led to overcrowding in the tank, further stressing the fish out. The angels and fighters probably hated each other and this would have stressed them out too, and the female fighters would have gave the male fighter a terrible time.
If you want to keep angels, you'll have to keep very peaceful fish who won't nip at their fins. You'll also have to aviod small fish like guppies and tetras who'll end up as live food for the angels. Mollies are nice and peaceful who won't nip but as I said they prefer salty water. Corys are lovely wee bottom dwellers who won't bother your angels either. Their is so much choice, just don't listen to LFS's!!
I wish you all the best for your next tank set up and I'm glad you found the forum. I think most people here (inc me) found it after losing fish.
All the best.
P.S Your readings are spot on just now so don't remove fish without adding one to take it's place, if you see what I mean. Don't take the plec and fighter back until you know what you want to replace them with. And like before add new fish slowly.
