Can one machine virtually host a DNS server and an Email server?
Many (if not most) server roles are not mutually exclusive.
Running an authoritative name server for your own DNS domain and your email are not mutually exclusive either.
So yes, you can combine DNS with E-mail services on a single host.
Short Answer. Yes you can.
Remind, that I use also proxmox and using a DNS on the host since it reduces a lot of DNS traffic from or to the net devices.