Not sure if people have confirmed or denied this yet, but I can sort of speak to the whole 'freeze a thing in stasis, apply momentum/trajectory, get up on top... wheeeeeee?'
I walked in to Nintendo NY today, as I often do, to just watch some people play through the two demos (I had my glorious time with the game on Tues, managed to kill one of those grounded guardians!

) and get streetpasses and such. I get up there and they are in between demo appointments and a Nintendo rep is getting some time in the first open-world (non story) demo. We get the small talk out of the way, he's played the thing for several hours at this point during the week. I ask him about the riding-the-stasis object thing and his eyes widened immediately. He had to try this but realized he only had about 8-9 minutes left in the demo session. He managed to barely get there (a very fun and tense story in and of itself) and thus far I can say that results are inconclusive.
He got to the boulder outside of the stasis trial shrine, frose it, whapped it just a few quick times with the sledge hammer, climbed up top aaaaaaaand the boulder flew out from under Link and link dropped down to the ground (sorry I didnt get video), queue 'Thanks for Playing'. HOWEVER, the momentum and trajectory he applied was almost purely out in front of him, virtually no upward motion. Pretty sure there's some sort of a sweeping upward strike with the hammer and part of a combo. I suggested that if he gets another crack at it, he should try two things: apply more upward launch to the boulder before getting on, or much more importantly, apply a bunch of outward kinetic energy then grab on and start climbing but dont get up on top of the boulder. REMAIN LATCHED ON TO THE SIDE. he said he wouldnt get a chance for a few hours but he was looking forward to it.
Here's the thing though, we created an extremely fun and tense mini-adventure in the context of the time-limited task. He was by the cliff face that you'd need to climb to get to the shrine. He quickly gathered some rushrooms and stemella shrooms, cooked them up, chopped down the tree, crossed the small chasm, ate his speed increase skewer, started climbing and scaled the damn cliff in one go eating both of his stamina regeneration skewers along the way! He entered the shrine (skip cutscene), dashed through the shrine in record time, (cutscene skip), and had just enough time to experiment.
This game is truly going to have players authoring their own unique adventures at every turn, and I can easily see instances of the game setting you out on time sensitive tasks naturally without this specific case of a ticking clock demo.
GUYS WHAT ARE WE GOING TO DO FOR ~9 MONTHS!?!?!