Assuming you haven't actually attempted to rebuild a data disk while you had incorrect parity then your data should be fine. Each of your disks is independent, and bad parity doesn't have any effect on the data on those disks.
But, when you need to rebuild a data disk, parity must be correct, and every bit of parity plus every bit of ALL other disks must be reliably read in order to reliably rebuild a disk.
This is why we are always concerned with the health of EVERY disk in the array, regardless of how important its data is. Every disk is required for rebuilding any disk.
yes
The only correct answer is zero, and you need to get it to zero somehow. If another correcting parity check still doesn't fix it then you need to get to the bottom of the problem.