If we're being honest, no, I don't think this would be great off-ice training. Can it improve balance and utilize core strength your body isn't use to using? Absolutely. But training like this in the offseason is not going to be easy on the body and chances are you're taking away from more important off-ice training for an NHL player, because you're not going to gain anything from doing this twice a week for an hour, except strains, ligament tears, and other injuries that will probably carry into the season.
You're asking somebody to train 3 + hours a day, several times a week for months. That time is better served doing other off-ice training/weights/skating for a player like Laf, and most players in general. (Now Laf not doing that is another story..)
Yeah, most off-ice/off season hockey programs consist of hockey specific movements targeting explosiveness.
The pros/adults get crazy with adding heavier deadlifts and sled sprints, but for younger prospects its probably better perfecting body weight exercises and conditioning before getting up to that level.
A lot of what you see on Ninja Warrior is grip strength and building your latissimus dorsi region, with some balance thrown in. Most of it is literally recreating parts of the specific course and practicing the challenge over and over
I completed the The Program from Nike which was a 12 week dryland/offseason plan put together by Gary Roberts. Mainly for younger kids trying to reach the pro level. It was rigorous but really made a difference. It mixed together a lot of plyometrics, strength training, med ball and core work and in the later weeks implemented sprints and a focus on foot speed. It is really well thought out. Some of the exercises and warmups I still use before my games. The wall sits
Laf should be half way through this by now
Weeks 1-4 Speed & Power
Week 5 Active Recovery
Week 6-9 Explosiveness
Week 10 Active Recovery
Weeks 11-12 Training Camp
At his age/level he should be in the gym with Kreider doing the advanced stuff, working with a skating coach and building conditioning (running/steps)