I've had nothing but issues trying to run Ubuntu in Hyper-V. Even the Windows Ubuntu LTS image that comes with the quick-create didn't work for very long.

Not sure what I'm doing wrong, but I've never has success with non-windows OS's.

What host version? I'm running 18.04 on Server 2016, for reference, did absolutely nothing special or unique, downloaded the iso, built the machine and loaded it and it's up running dns & unifi controller 24/7 for my home network with no issues.

Can you run singularity-container or docker in your Linux guest?

I haven't had reason to try, but I can't imagine a good reason why one couldn't.

I would hope so, as that is what the Win10 version of Docker-for-Windows does.

Yes