Drive Configuration In Virtual Environment
I think it comes down to the IO subsystem your vendor is using. If it is still spinning disks, then for performance purposes, what you suggested is best practice. However nowadays, with all-flash storage arrays (SSDs), there are no moving parts, thus the IO patterns are not much of a concern anymore. 

Bottom line, your vendor should be well-versed with what best practice is for SQL Server install. I suggest asking for supporting documentation to be safe. For example, VMWare has a SQL Server on VMWare Best Practices Guide.pdf which pretty much spells out the above.