Re full flap takeoff and the C150.
When I did my PPL near Montreal we were practicing PFL's in the C150 one very hot muggy summer day with myself, my 180 lb instructor, and nearly full tanks. The last when went pretty well and at 300 ft AGL with 40 deg flaps out I was told to go around. Full power and flaps up......only the flaps did not move. At full power the aircraft would just maintain level flight and would not climb. We flew the 10 miles back at 300 ft and landed. This was 33 yrs ago but it is still a rather vivid memory and after that I am carefull with large flap settings and low powered Cessna's.....
As a young Instructor/charter pilot I once used 40 deg of flap in a C 172 to get it to lift off from a very muddy field. The aircraft would not accelerate above 45 kts so a sudden application of 40 deg flap caused the aircraft to balloon up enough to break free and then some carefull stick jockeying kept it in the air as I slowly accelerated to a sensible speed. When I returned the CFI/Chief Pilot asked why the aircraft was covered in mud. When I explained he said "Good Flying, Now WTF were you doing going into the field in that first place"
That being said the use of large amounts of flap on takeoff is common with float plane takeoffs. The C180/185 manual flap systemis is particualy usefull as you can finesse that little bit extra bit of flap between the 20 and 30 deg notches to help the aircraft break free of the water when it is heavily loaded and/or the wind is calm