Some advice for shared folders and jails apps

[WhiteTiger]

On a VM in VMware Workstation I am testing what will be a NAS in production.
The NAS (quad core, 16GB) has 1 SSD 120GB per boot, 4 HDDs of 1TB in RAID-Z1, 1 HDD of 500GB that I have not yet decided how to use, perhaps for snapshot.

5 users will have to use it, plus an admin.
Each user will have his own "home" folder and will have access with different rights on 8 shared folders. One of these users has a "master" role and will have access to all folders, including personal homes.
This user should also have access to limited NAS management functions, at least to create users and user groups as well as to change access rights.
Obviously the admin will have access to everything.
Finally I planned to install:

1. Clamav;
2. a software for remote backup;
3. a software that acts as a backup server for the 5 PCs;
4. NextCloud for sharing some shared folders on smartphones.

Activating snapshots will provide me with a local data save.
Users will also have access to the NAS from their home through OpenVPN installed on the firewall.

With a VM I can do multiple tests and restore the previous conditions. Nonetheless, I am running in circles on the configuration.

I have created 10 user groups:

• 8 have R/W rights on each shared folder;
• one is the "Master" group with users who have full access to the folders;
• the last group is the one that identifies users with fewer NAS management rights.

What confuses me is how to create the folder structure using zvol, dataset and shared folders.

I thought about creating:

1. "Home" dataset as the root of personal folders; in this manner each user can save whatever he wants. Alternatively, create sub-folders, one for each user to set single quote value.
2. "Company-Name" dataset as the root of the shared folders.

Where do I create the jails for the various apps?
Should I use the 500GB disk only for snapshots?
Can Nextcloud be associated with one or more shared folders?

What do you think?
Do you have any advice for me?