" any champagne, except perhaps Natural (drier than sec), might work."
You mean Brut Nature is drier than Brut I assume? Usually driest to sweetest is Brut Nature, Extra Brut, Brut, Sec (occasionally labeled extra dry like with White Srar), Demi-Sec, and Doux. Though I've not seen the latter in US markets. Occasionally see some demi-secs- actually carried my lone bottle of Pehu Simonet Gourmandise Demi Sec to a party last week (well, it said cake and Champagne), but never got to taste it.

I'm going to give Brut Champagne and edamame a try. Maybe a Kabinett (traditionally styled) as well- not sure why sugar and soy beans would be a problem.