The jolly businessman with whom Scrooge apprenticed, Fezziwig appears in the one happy memory of Christmas Past.
If Marley is the worst-case scenario, then Fezziwig is the best case.
On the one hand, he is clearly a good moneylender, which we can judge by the fact that he trains Scrooge to become a pretty good one himself. But on the other hand, he's not above throwing an epic party for all the local apprentices and then busting out with a few awesome dance moves himself.
Check out this description of him with his wife:
[O]ld Fezziwig stood out to dance with Mrs. Fezziwig. […]
[O]ld Fezziwig would have been a match for [any of the young dancers], and so would Mrs. Fezziwig. As to her, she was worthy to be his partner in every sense of the term. (2.94-95)
And yes, we're pretty sure that "partner" business really is meant to imply that they are a good team in the boardroom and in the bedroom.
By throwing him into the mix as an example of an apparently successful businessman who is nevertheless able to also function as a human being, Dickens side-steps the usual criticism that was hurled at his novels—that he understood bupkis about how business actually worked and so maybe should butt out of the capitalism question altogether.
This way, he shows his readers that he knows what's up, and that it is possible for the moneymakers to have their cake, and share some, too.