It sounds like you handled the situation about as well as you could once you realized what the problem was. (with the amonia I mean) Normally when fish are used for cycling, only a few are added, and only hardy species. However, I know I made similar mistakes when I got back into fish keeping a couple years ago! Anyway, like I said, the regular water changes really helped keep the death toll down. It's all you could have done short of returning half the fish.
Your tank is about fully stocked now, so I would not advise getting any more fish. The common plecs will grow fast if properly fed (they need vegetables and algae pellets, they can't survive well just cleaning algae from your tank) They will probably be the first to outgrow your current tank, and easily get over 1 foot long. The clown loach maxes out at 8-12 inches in a aquarium I think, but it is slower growing than the plecos.
I got a common pleco about a year ago which was 3.5 inches long, and it is now 8.5 inches long. (and still growing) I am now looking into getting a 6 foot tank for him, as my 55 gallon is not going to be very ideal for him much longer. ( when I got him for my 29 gallon, I didn't know any better either )
When you turn out the fish tank lights and look through the tank - if it looks green you have algae in the water also. This is caused by having the light on too long, overfeeding the fish, and some other factors. It is best to buy a $5 timer for the tank light, and keep it on for only 8-10 hours per day. Many people recomment having it shut off for a couple hours in the middle of that 8-10 hour period also. If you feed your fish more than once per day, you may consider reducing it to once per day if your cloudy water continues.
Best of luck with your tank!