Does this functionality work when MGL N16 Nav radio and Vega are installed on a serial port in Skyview HDX?
The NAVALL mode you have shown displays the Vega in SCAN mode. I've not had the opportunity to test this mode with VOR as the primary frequency and an ILS in the secondary frequency, but I have played with two VOR frequencies. The depicted radial for the primary frequency on the N16 can be shown as the SV HSI's bearing pointer and (if selected as the nav source) the OBS will set the desired course on the HSI. Whether it is SV pointer #1 or #2 depends on how you have named your NAV radios. In my case I've got my N16 as NAV 1 (N16 > MGL CANBUS > Vega > RS232 SL30 emulation > SV serial port) and my Avidyne IFD 540's VHF NAV as NAV 2 (IFD 540 > ARINC bus > SV-ARINC-429 > Dynon network > SkyView).
This is really getting down into the weeds here, but SV bearing pointers supposedly have the capability to depict the NAV 1 standby radial (in SV speak, secondary frequency radial in Vega speak) as a bearing pointer, but I've yet to discover how to get that to work. This dovetails into your question: other than that standby radial, no other secondary frequency related information is sent from the Vega to SkyView. If what I suspect you are looking to do is to fly a specific VOR radial in order to intercept an ILS final, you would need to flip flop the example picture's frequencies to send the ILS info to SV's HSI as soon as the REALLY tiny localizer display on the Vega became active, in order to complete the intercept on SV.
Now to go even deeper into the weeds. Just one problem with the above scenario: even though it would work, it's technically not 'legal' to use your N16 as a primary IFR nav source
if it's in the SCAN mode because both the letter ID and aural identifiers are only available with the SCAN mode OFF. With SCAN active the radio continually switches frequencies rapidly back and fourth, too fast to pick up an identifier that's transmitted at human hearing speeds. In the OFF mode, the bottom frequency becomes grayed out and is just a standby frequency display. The radio listens to the primary identifier, decodes it, and puts the identifier's letters on the screen. The aural identifier also becomes available for us 'old school' types.
The phrase 'Tune, Identify, Monitor' may be faintly remembered by some from their instrument training days, but I'd bet a fair number of folks skip the Identify part if the radial looks right, and precious few actually continually Monitor the aural identifier (even low in the background) as is technically required. Many modern systems, N16 included, have the ability to listen to the aural identifier and decode it for the pilot, and having the letters of the ID on your PFD also satisfies the Monitor requirement. Recall that a VOR display that appears correct is still not legal to use unless the aural identifier is also good, since one of the methods used by electronics techs to indicate the signal may be inaccurate during maintenance is to remove the aural identifier, leaving nothing to decode for the PFD.