It may be possible to launch local Office exes via Tim Mangan's latest PSF.
It may also be possible to mess with ImageExecutionOptions keys to replicate RunVirtual in App-V.
I have not tried either (yet). Good luck, but I wouldn't hold out much hope for a bug free experience that you'd want to put into production. Doing this with App-V caused all kinds of issues, I think we'd be best waiting for an MSIX-native version of Office.