you can never go wrong with a gopro, i have one and its epic.
some of the tasks you said sound like the weight of the gopro might inter fear.
but it will be fine on the helmets. and with the gopro if you get the sukshon up you can stick it anywhere (stick it to of boards in the corner looking down. it would be a great shot and do a drill with digging for the puck in the corner. great view on the play and skills.
and with the gopro it has a really wide lense. so it gets everything
Reminder i have never used a contour or seen one. so my opinion is kind of one sided. but i know gopro is great. but size/weight is something you might wanna check