Ooh I have some Wonka questions!
What are Wonka’s favorite treats, favorite dance, and favorite book?
Does Wonka have any interest in history or different eras of time (for example Regency, Edwardian, or Victorian)?
It appears to be Wonka Question Time yet again...
What are Wonka’s favorite treats?
As for chocolate and candies, he would never eat any that were not his own creations. He would/could never in good conscience support his competitors' businesses, buy from them or try any of their sweets.
I also perceive Wonka as being somewhat of a germaphobe or at least considerate of guidelines in terms of having clean hands, limiting how much he touches the food he's eating/serving, etc. so I think it would take some time for him to warm up to the idea of someone else preparing food for him to eat.
Now, if we're talking baked goods, Wonka would prefer chocolate (obviously) flavored desserts — dark chocolate being his favorite.
I think he would prefer pie a bit more to cake, but he's not so picky that he'd turn his nose up at being offered a nice treat.
I think he would also enjoy macarons.
Something a little less sugary that he would love are rosemary rolls.
I answered this a bit already: here.
I can see Wonka being interested in ballroom dancing, but I think his main interests lie in literature, language, etc. which are all things he can do alone, teach himself, etc.
Dancing (usually) requires at least two people and since Wonka has been isolated from society for many years, there are not very many opportunities for him to dance. He draws on his knowledge of dancing from his younger years and from what he has read in books.
He isn't a bad dancer; there have simply not been enough opportunities for him to practice.
I already have answered this question more thoroughly: here.
I think that picking a favorite book would be difficult for Wonka.
He quotes Shakespeare quite often, so I think that among his favorite books would be a collection of Shakespeare's plays and writings.
He strikes me as a poetry lover as well.
Some writers he would like (and quotes in canon): Oscar Wilde, John Keats and Arthur O'Shaughnessy.
Does Wonka have any interest in history or different eras of time (for example Regency, Edwardian, or Victorian)?
I think Wonka's interests stretch far and wide, even with history. He would be curious to learn as much as he can and I don't think he would be particularly drawn to any specific era of time.
Wonka strikes me as someone who wishes to collect knowledge and to learn because he values intellect and the hunger for knowledge. At least, it was what kept him occupied when his factory was closed down and he had not found help from the Oompa-Loompas yet.
I think that whichever era he is studying at the time would be what he would sink into.
It's all a matter of circumstance — he is always curious.
