Bleechme ~ Well, it's up to you what you do. It's just a wanring though. It's very hard to get rid of CAEs, because most fish stores won't take fish back, and not a lot of people want them because of the aggression. If you have a tank that would be suitable for them to live in, by all means keep him. It saves one more beginner from getting that fish. Otos would work for your tank, but I'd get a few more then three with that size to work with. 
I noticed that getting some of each kind of Livebearer you want to breed was mentioned. That's a good idea, however consider the Mollies and their salt requirements (as bleechme said, and as is mentioned in the pinned topic). The other Livebearers should be fine with some added salt, however the other fish you stock with them will have to be able to tolerate salt too. It's something to be careful with.
I noticed that getting some of each kind of Livebearer you want to breed was mentioned. That's a good idea, however consider the Mollies and their salt requirements (as bleechme said, and as is mentioned in the pinned topic). The other Livebearers should be fine with some added salt, however the other fish you stock with them will have to be able to tolerate salt too. It's something to be careful with.
