I’m curious about point #2 on this post.
What would happen if you manually create an .ix-virt dataset in advance, then set its compression and recordsize policy?
Will it be overridden when you set a “default pool” for Incus for the first time?
Do child datasets (i.e, each “Linux container”) inherit the .ix-virt parent dataset properties?
EDIT: I see @Stux is replying. I don’t often like to gamble with my money, but what’s the over-under of the next reply being a link to a YouTube video? 
EDIT 2: I just lost $500 USD by placing a bet that the next reply would be a YouTube video. 