What you might want to do instead, is make a Local Pool 1 which holds local drives A-E, rename your cloud pool to Cloud Pool 1, and then make a Master Pool that holds Local Pool 1 and Cloud Pool 1. It's easier if different levels have different nomenclature (numbers vs letters at each level).
Master Pool (2x duplication)
Local Pool 1 (any duplication you want)
Local Drive A
Local Drive B
Local Drive C
Local Drive D
Local Drive E
Cloud Pool 1 (no duplication)
FTP Drive A
B2 Drive A
Google Drive Drive A
Note that with this architecture, your cloud drive space needs to be equal to the size of your Local Pool 1, so that 2x duplication on the Top Pool can happen correctly.
If the FTP Drive A goes kaput, Cloud Pool 1 can pull any files it needs from Local Pool 1, since they are all duplicated there. Local Pool 1 doesn't need duplication, since it's files are all over on Cloud Pool 1 also. You can (if you want) give it duplication for redundancy in case one of the cloud sources isn't available - your choice.
As an alternate architecture, you can leverage your separate cloud spaces to each mirror a small group of local files:
Master Pool (no duplication)
Pool 1 (2x duplication)
Local Pool A (no duplication)
Local Drive a
Local Drive b
Cloud Pool A (no duplication)
FTP Drive
Pool 2 (2x duplication)
Local Pool B (no duplication)
Local Drive c
Local Drive d
Cloud Pool B (no duplication)
B2 Drive
Pool 3 (2x duplication)
Local Pool C (no duplication)
Local Drive e
Cloud Pool C (no duplication)
Google Drive
What this does is allow each separate cloud drive space to backup a pair of drives, or single drive. It might be more advantageous if your cloud space varies a lot, and you want to give limited cloud space to a single drive (like in Pool 3).
Sorry, I think I misunderstood your goals in the first post.
As long as your cloud pool is just a member drive of the larger pool, and you have at minimum 2x pool duplication on the main pool, then you'd be covered against any failure of the cloud pool, yes. But if you lost 2 or more of the local drives and those were the sole holders of a file that was duplicated, the cloud drive wouldn't save you, the data would still be lost.
It looks like you're relying on local drives for redundancy, and the cloud drives for expansion. Normally it's the other way around.
