Chaz ,
As I understand , there are 2 faulty drives (1:6 and 1:13). I would advise to remove these drives if HPE support has told you the same is faulty. MSA Gen2 lets you add 8 spares. You may find this detail in the CLI guide :
https://support.hpe.com/hpsc/doc/public/display?docId=emr_na-c01755995
(Page : 110)
You could try adding spares via CLI also . Please let me know the error message you can see when trying to add the spares.
Since , I do not have complete details or logs , I have answered this question on best effort basis.
Please share the error message here or you may log a support case with HPE if any issues. We will help you further.
I am an HPE Employee