Q: Is there any particular problem hosting a file share on a Hyper-V server that will be used by virtual machines on that Hyper-V server?

A: The best practice for a Hyper-V server is to not run any other roles on that server. It's possible to host an SMB share on a Hyper-V host that's used by virtual machines. However, that network traffic would be handled entirely by the CPU on the Hyper-V server, with no traffic actually touching a physical network card. This means no offloading of traffic processing to the NIC, meaning the CPU has to do all the work—which isn't a good thing. Therefore, although it's possible to host a share on a Hyper-V host used by virtual machines, doing so isn't recommended.