So I read about monowall recommending OPNsense and decided to give it a try - after installing (without reading much ahead) I realised it supports the Hyper-V network interfaces by default.
Keep in mind that 16.1 will most likely not work on Hyper-V 2012 R2.
This is based on FreeBSD, not Linux. But why do you not install the tools?
For newer FreeBSD releases, BIS is built in to the FreeBSD operating system, and no separate download or installation is required except for a KVP ports download that is needed for FreeBSD 10.0.
You have one physical NIC which you use as a uplink for a VMswitch.There is no way to have a VMswitch with two virtual networks unless you use VLANs.I doubt pfsense can do what you describe. It just doesn't make any sense based on what you describe.