Hi Roger - Yes, that was the reason they recommended using disks as RAID 0 - to gain full access to the drive for ZFS. If you're interested, the blog is https://calomel.org/zfs_raid_speed_capacity.html -- They were using an LSI MegaRAID 9265-8i
Yes, people have done that but many of the experts here (of which I am not one) will advise someone in that position to get a new controller instead. You often can't get access to SMART data on the drives, and perhaps other mysterious things happen if you use RAID 0 underneath ZFS. But if it isn't an option with your board that's no problem!