The tail surfaces seem to indicate one of the Goldberg Falcon family Falcon Jr., Falcon 3 or Falcon 56. The twenty five class engine would be the one to use for that airplane, not a forty that is if you wanted to use it to learn to fly with. The floats are indeed Gee Bee's.

The larger engine is likely an OS .40FP and that carb is a dead ringer for an FP bleeder carb however the red color makes no sense at all.

John