Upgrade/Migration from SQL Server 2008 R2 to SQL Server 2016
It sounds like your plan is to do an in place upgrade of the OS and the SQL Server. You will experience much less pain and have greater chance for rollback in the event things go awry if you do a side by side upgrade. 

Build up the new servers and then migrate to them. This keeps the existing servers working and allows you to migrate and test without affecting the users and data. 

Keep in mind too, that there could be many changes that could adversely affect the applications supported by this SQL Server. Having the extra servers will provide the ability to test those applications and find out what mitigation tasks you may need to take. 

Once you have the tasks and migration process detailed out, you can utilize log shipping from the main server to the new server to facilitate a low downtime migration. 

Also consider using Always On Availability Groups instead of clustering as it may provide you a better HA/DR. 

From a host name not changing perspective, utilize CNAME DNS entries. This way you can use new servers, and then when ready cut the DNS entry over to the new server name. To the users, they think nothing has changed.