Tested as Andrew stated on DVD connected to TV and it works but does not distinguish between MPEG-2 and MPEG-3 -- it just reports as MPEG.  And mp3 works too on DVD.

FYI -- you will have to edit dvd.sh to change ac3 extension to mp3 (file written as mp3 but really mp2).  I did not add -L 48000:2:16 as not needed (?).

And execute dvd.sh after like for lpcm.

Is it possible to get MP2 audio; if possible how and where to set it on the create DVD or Batch render window?
I tried to check FFmpeg there, but could not see MP2.

try "MPEG AUDIO" and select "II" in settings ...?