Hi Maggie,

Apologies for kvetching, but according to several pieces I've read in the past, John Stanley was one of the lead writers on Oswald (and many other Lantz characters) before his tenure with Little Lulu began: http://www.fmydesign.com/stanleyisms.htm
"The Great Egg Hunt" certainly seems to contain numerous Stanleyisms, most obviously characters repeatedly shouting "Yow!" This would suggest that Stanley, rather than Walt Kelly, is the scripter of the story -- making the reference to his name on the page you've reprinted a kind of signature (in the otherwise creditless comic), rather than a tribute.
That said, I absolutely agree with you that the art is in part Kelly's throughout the story. It's almost as if everyone but Oswald and Toby themselves resemble Kelly designs.