RE: Suggestions for third plane
The Funtana 90 is popular at my field. Start it tame, then you can increase the control throws and move the CG back if you want.
There are any number of acrobatic planes in that size range, things like Extra's and so on. If you go easy, and keep it conservitive on the CG and control throws, and watch for stalls, you should be ok.
A smaller step might be the ultra stick 120.
There are a bunch of pattern-type planes that might be good options as well. They are smooth flyers with very few (if any) bad habits, and are pretty easy to fly if you keep the speed down.