The answer is pretty simple and also answered in our
audio wiki… Vero simply can’t output DSD via pass-through. There’s a HDMI spec for it, but it’s not something that any Kodi device we know of has implemented. Not all AVR support that pass-through format, but some do.
Pretty unlikely really as it’s not a common case. @grahamh might be able to say more about this, but energy in our small team will most likely be directed elsewhere 
But we’re always listening to requests and if something gets enough support, we might look into it (not a guarantee that it will happen then either, for various reasons).
MLP is simply a packaging format for PCM audio, so nothing special to pass-through here.