It’s hard to say if this is just for testing, but the current Beta appears to have a longer timer for the Challenge Event, around 5 days.
EDIT: I added some more information on that to the top post too
No, none of the current Completion Rewards contain 4* Ascension Materials. I’ve posted the Rare and Epic Tier Rewards in the top post of this thread, and will be adding the Legendary ones shortly, but they also don’t contain any 4* AM in the Completion Reward.