- (a) If the Hyper-V host server is Essentials, you could only install one instance of Essentials as a virtual machine on this server. And this host server can only run Hyper-V role with none of the other roles and features of the Essentials Experience installed. (b)If the Hyper-V host server is not Essentials, yes you can install two VM running W19 Essentials. Fore more details
https://social.technet.microsoft.com/Forums/en-US/1515015a-55d7-411e-a181-41e4dc97b807/hyperv-support-and-licencing-in-windows-server-essentials-2019?forum=winserverhyperv - Yes, you need to purchase separate license for each instance.
- No, essential server should be root domain controller, each domain has only one root DC.
- There should be no licensing issue if the essentials server is used for a web server. For more details
https://community.spiceworks.com/topic/1992191-does-accessing-iis-website-over-internet-browser-need-cal-license
Please Note: Since the web site is not hosted by Microsoft, the link may change without notice. Microsoft does not guarantee the accuracy of this information.
Thanks,
Eleven