I came across this solution [
https://github.com/DDoSolitary/LxRunOffline ] recently which works like a charm and I wonder if it might be a direction for vagrant on windows 10 that potentially gets around common problems with hyperv and wsl.
Basically, it allows you to create and manage multiple WSL environments File permissions will still have the former issues I expect but i think it may be the easier way to get around many other issues...