After the data aggr is deleted, the "disks" (partitions) will just be returned back to the spare pool. The root aggr will remain intact.
zero them out and they'll be ready to be added to a new aggr(s) If you need to reassign the disks/partitions betweent the two controllers you use "-data" flag with the disk sub commands.
e.g:
disk removeowner -disk x.x.x -data true
disk assign -disk x.x.x -data true -owner NODEx
This command to show what is assigned where.
disk show -fields data-owner, root-owner
How do you plan to create the new aggr? and why is it needing to be deleted/recreated. I can only think of a few reasons to do that.