Using/Substituting a Coin Cell Battery
The PR48 may be rated for 1.4 volts "nominal", but if you inspect the data sheet closely, the actual voltage is closer to 1.15v to 1.2v. Not sure if your bluetooth could run with 1.2 + 1.2 = 2.4 volts.   Doesn't look too good as far as voltage is concerned.  The CR2032 does show about 3 volts under load.  

I was surprised at the ampacity of the zinc air (even though I use them and wear a hearing aid, I had never looked up the ampacity of zinc air.  

EDIT :  Added link to CR2032 : http://na.industrial.panasonic.com/sites/default/pidsa/files/crseries_datasheets_merged.pdf