Multiple sites sharing the same MySQL database but different information

[Cucaracha]

Hi please excuse me if this information is somewhere else i tried a thorough search and i'm very new to this.

First: My scenario is i have one domain and multiple sub-domains, each domain is running a separate shop for each of my agents, each agent with a separate paypal account for their own shop.

Secondly: I have one MySQL database to host all the separate shops with each shop acting as completely separate entities with no information being shared between them.

Is this set up possible? if not what are the limiting issues?

Can i assign table prefixes during installation to each instance of Zen Cart fopr the SQL?

And finally are there issues with SSL if i set up different shops on the same domain, with different merchant accounts like paypal?

Many thanks in advance...