Are you planning to run the 2016 as domain controller in the existing domain? if so, you need to prepare the domain (adprep /domainprep, adpre /schemaprep, adprep /forestprep) schema preparation, forest preparation.
I rated Ganesamoorthy S extremely helpful because of the link provided in the answer.
The other two were also correct.
Windows OS
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It will run 180 days without activation.