Firstly, thank you for the time you have spent on this. It really means a lot.

I can see the drivers on the disk utility when I mounted the external hard drive in order to back up the files.

I would also like to note that the RAID array has not started. According to the disk utility there are missing components.

When I typed:

$ extundelete /dev/sda or /dev/sdb

The result is 

No action specified; implying --superblock.

extundelete failed to read-only open device "/dev/sdb": Error code 13

When I type

 $ extundelete /dev/sdb2

I still get

No action specified; implying --superblock.

exyundelete: stat "/dev/sdb2": No such file or directory

 
The when I ran the fdisk -l, it showed me that there was indeed an sdb2 and an sda2.