After uninitializing both drives of the array, is the data overwritten and unrecoverable or can it be recovered?
More aboutuninitializing raid array
It depends on what you mean by uninitializing. Breaking the RAID doesn't destroy the data. If they contain private info, you need to wipe the drives clean with DBAN or similar software or physically destroy them.
RAID1 is a mirror raid. uninitializing (as you called it) /delete/remove raid set... data still there