13yrold: In many respects fun fly stuff is really 3D. I was trying to avoid an issue by mentioning both. What one calls "3D" another will call something else. So, as for learning fun fly before 3D... they are basically the same thing to most. I'd say you should have a basic handle on traditional aerobatics before learning 3D/Fun fly. It sounds like you already have some basics aerobatic skills, so if you want to learn 3D, go for it.

There is no need for flaps on any fun fly type plane. They (fun fly types like the SE, uproar, etc) typically have very high lift / high drag wings to begin with, flaps won't add much to what is already there. You can however use a flaperon mix, which causes both ailerons to move in conjunction with the elevator. Flaperon will often improve pitch control on a fun fly plane. You can also use an airbrake (raise both ailerons) to control speed in very steep dives.

Yes, I have built and flown a Sig SE.