RE: First Float?
Just about anything can be adapted to floats, one of my first was an extra 230 with a single float set up, I also has a great planes Super Decathlon,, both very aerobatic but not scale in the sense you'd see a full scale version on floats set up that way.
My question is when you say preferably a scale plane, at least somewhat aerobatic,, do you mean a scale float plane as in a true full scale float plane, or a scale model adapted to floats??
Many guys choose a Cub for a first plane, only a baby step above a trainer for sure, they are "scale" and somewhat aerobatic,, clip the wings and they are even more snappy,,