Varieton was a popular label of the popular record-subscription club that also produced the “MMS” and “Concert Hall” classical recording as well as various other, less commonly encountered labels. All of these are rather infamous for the fantastic pseudonyms used whenever artists were employed that had exclusive contracts elsewhere. This might be the reason you couldn’t find out much about the artists here – quite possibly they went by very different names for the rest of their careers! For an overview of the enterprise look here (mainly from the classical viewpoint, but a Varieton EP is pictured near the bottom of the page):
http://www.soundfountain.com/concert-hall/concerthall.html
Keep up the good work!
Chris