Symantec Backup Exc 15 license

1) There is OnPremise and there is Cloud Platform licenses. OnPremise means the license is for the software which is installed on your premises and not on Cloud.

2) Hyper-V License already  includes the Remote Agents for the VMs. So no need to buy Remote Agent licenses for VMs. The only time you would need additional licneses for the VMs is if the VMs are running an application such as AD, Exchange, SQL, Sharepoint and you want to use Application GRT, then Agent for Application & Database license is required, else not.

3) Licenses do not expire, though Support (Maintenance) contracts do. Upgrade is free is the Support Contract is valid. If this contract expires, then upgrade comes at a cost. In your case, the contract is valid until Jan 20, 2017. If you upgrade before this date, then upgrade is free.