Yes the is is on one of the pairs.

I'll see what the controller is today. What should I be looking for to determine capacity limits?

I did find SSD adapters.

I was definitely worried about mixing HDD and SSD during the migration. Think there could be problems there?

There's already a backup in place so that's good.

I've been reading some very negative opinions around the web about throwing consumer SSDs into a server. Also some horror stories...