I got some idea but I need more details:
Right, assume each containers will host Wordpress or CMS, although reading the other discussions lead to more questions.
How does the hard limits on CPU and memory looks like?
Swap to buffer refer to virtual memory on disk?
Shared DB in a single container meant in LXC container or host (non-container)?
Is it recommend to run MySQL and Postgres in zfs or stick ext4 in my scenario?
How would you advice on the snapshot and backup snapshot in the event of system failure?
Doe it require an exact amount of storage space to store a snapshot?