You must use the VOR for distance reference, but other than that, the "nominated" aid could be either the VOR or NDB as mentioned on the sector definition.
The missed approach point is also defined as either aid and as both aids are defined (freq and ident) on the plate, you are correct.
Notice the VOR and NDB approach plates (for which you must use the named aid) do not define the other aid.
ps, Aussie, a Sector A arrival is the ONLY available approach, there isn't a B or direct track...
