I can't comment on the 2nd flick but with the beaver, there is a few issues that in my point of view that contributed to the accident.
Unstable approach, a definite no-no when landing on glassy water. Secondly, not straight ....too much left yaw. Finally in my opinion, the main problem was that he was too nose low for what appears to be Whipline floats. Touching down further back on the heels will can in most cases correct the first 2 issues.
Wether you have the water rudders up or down is irrelevant. They are spring loaded and will bounce up on touchdown if indeed they have not been retracted. However, you can expect some damage to the brackets!
FJ 01