This site [1] discusses pretty much what you are asking (all networking going through a virtualbox pfSense) however it's written for windows 7, not sure if this still works for 8-10
I would think if you set up the VM to deny everything coming from windows, and allow anything coming from the other linux VM it should work fine (just set up multiple NICs in the pfSense VM and have the linux VM go in through a different NIC than the host windows)
I personally do something similar with linux on linux where I have the host linux be allowed to only reach my internal network and the debian mirrors directly, and anything else is done through VMs.
http://timita.org/wordpress/2011/07/29/protect-your-windows-...
I would think if you set up the VM to deny everything coming from windows, and allow anything coming from the other linux VM it should work fine (just set up multiple NICs in the pfSense VM and have the linux VM go in through a different NIC than the host windows)
I personally do something similar with linux on linux where I have the host linux be allowed to only reach my internal network and the debian mirrors directly, and anything else is done through VMs.