During the Nowhere to Go but Up sequence, when everyone floats away on balloons, Gooding is clinging to Frye rather than floating on a balloon of his own. Why? Because he had much more enthusiastically assisted Wilkins in screwing over the Banks family than Frye did, so much like Wilkins, a balloon wouldn't work for him. Although unlike Wilkins, he seemed willing to see the error of his ways and give good-natured whimsy a chance, hence why Frye apparently let him share a balloon.
During A Conversation, Michael asks the biggest question on his mind, the one he says he most longs to know: "My question, Kate, is: Where'd you go?" Of course, Mary has the answer: The Place Where Lost Things Go.
Jane becomes an activist like her mother, but how did this upper middle class girl end up fighting for the working class specifically? Perhaps her friendship with Bert and the other chimney sweeps led to her learning about the not so magical aspects of their lives.
Wilkins may not just be a Morally Bankrupt Banker in attempting to seize the Banks' house. Remember that Michael made a ruckus about investing tuppence into the bank, hoping to donate it to "feed the birds" instead. This resulted in the bank suffering a significant loss as his outburst when the phrase "they're stealing my money" spread out like dominoes. He may be hoping to get back at him this way in particular.
And how does he get his revenge? By stealing Michael's money.
Mary Poppins acts the proper English lady, speaking the Queen's English at all times, and always agrees reluctantly (or seems to) to any suggestion or idea placed before her, often with a deep sigh and an "oh, very well." When on stage, she can't help but cut loose into a bawdy Cabaret-style number, slip into a heavy Cockney accent, and agree enthusiastically to every idea. A Cover is Not the Book, indeed.
Speaking of that sequence, her accent change makes for a nice homage to English music halls of that day and age; much like the American Vaudeville, it was a place of lower class performers entertaining their kind. A cockney accent and a bawdy number, both usually associated with lower classes, are very appropriate considering all that.
Mr. Dawes Jr's claim that the Michael's tuppence had grown into a large enough sum to pay off the loan on his house seems... outlandish. His mention of "clever investments" seems to suggest the possibility that he's lying about the source of the money. Either he paid it off with his own money, or, being the guy who runs the bank, he decided to just forgive the loan with a cover story to let Michael save face.
On the other hand, given Michael's absent-mindedness where it comes to money, it also seems perfectly likely that he just doesn't know he's financially well-off.
What does Mary Poppins do to the wolf and his associates after discovering his deception and attempts to harm the kids?
If the animated world has some sort of prison, they most likely would have been thrown in there.