So far as I can tell, from searching on-line and quizzing Dick Greenhaus, Cousin Emmy is completely and totally out of print (except maybe her disk with NLCR).
Two summers ago at Elkins I met a gentleman who said his hobby was downloading commercial recordings, and played several bands -all quite good - including Cousin Emmy singing Pretty Little Miss out in the Garden. He said he would share his stuff at cost, and invited us to e-mail him. I tried that, and got no response. Then after a while, I searched the web for any reference to her recordings, and came up only with mentions of her name.
If my acquaintance at Elkins could find and download that recording, I assume savvy persons can do it. If any one can tell me how, I will be forever grateful.