This mod doesn't support Linux because TF2 for Linux doesn't include a compatible version of studiomdl, which probably wouldn't work in WINE. There's literally nothing I could do to support Linux, even if it was feasible for me.
As for why an outputted VPK doesn't work with some HUDs, sorry, no clue. It should work with all HUDs because it doesn't change anything that a HUD would change.