In the third Mary Marvel story of her series, "A Telegram to Adventure" (Wow 11, March 10, 1943) the Bromfield butler Jives is introduced (Mary Batson Bromfield and her foster-mother had a different-looking butler called Peeves in the first story). We're told that "Jives is an addict of detective stories! And because of that, his imagination is a little 'overworked'!" When he trails Mary to discover the job she's keeping secret (telegram messenger), he lets a gang think he's English Harry, the slickest crook in the rackets.
The Wayne butler Alfred first appears in Batman 15 (April-May, 1943). Alfred, too, fancies himself a criminologist—on the splash page of "Here Comes Alfred" he's wearing a Sherlock Holmes deerstalker cap. These issues of Batman from DC and Wow from Fawcett would have been in production at about the same time.
Alfred's first story was written by Don Cameron. But Jives's was by Batman co-creator Bill Finger.
This post explains how a particular Captain America story jumped out at me as Finger's. The same writerly trademark is in "Telegram to Adventure": the throat-clearing "Arrumph," a spelling without an initial "H" used by no one else that I know of. As Mary can tell, Jives harrumphs when he lies, and so this becomes a plot point. (Mary winks at the readers with an "Arrumph" herself in the final panel.) When I encountered this I thought "Bill Finger???" only to find that, according to the Who's Who, he was indeed at Fawcett—known to be writing Captain Marvel, at any rate—in 1942-3.
Jives amateur-sleuths again in the next story, "Mary Marvel and the Anxious Auctioneer," (Wow 16, April 7, '43) and this time he wears the deerstalker cap. But here the writer is Joe Millard.
I won't try to guess at the Mary Marvel artists. I suppose Marc Swayze may be in there somewhere, but this is the point at which Fawcett starts using multiple artists in the production-line shop system on some features. That the Mary Marvel figures are by different artists than the secondary figures becomes more and more obvious over the next few issues of Wow.