Formatting NFTS to FAT32

Ok, silly me.  I can’t format these drives if Windows can’t actually access them can I? 

Since the MyBook is set to RAID1 already - If I take each drive out and format them individually to FAT32 and stick them back in the MyBook enclosure … will THAT work?   The RAID designation is contolled by the MyBook unit and not part of the drive formatting, correct?