Hi Syed,
RBAC is simply giving a user specific roles on a piece of software and is in no way related to multi-tenancy which allows multiple clients to share the same platform without seeing each others' data/infrastructure.
1. Check the TN below as it should help you:
https://support.symantec.com/en_US/article.HOWTO81067.html
The various admin guides should also indicate whether or not the products are truely capable of multi-tenancy, and they're worth getting hold of anyway.
2. Symantec have a number of cloud-based offerings which are listed below"
https://www.symantec.com/solutions/cloud-security
If you sign with Symantec, these should be hosted on their own infrastructure, although public cloud providers like AWS and Azure do allow integration.
3. Check below, but you might also want to consult with a licensing expert around this:
https://support.symantec.com/en_US/article.HOWTO127746.html
Thanks!