The problem is you would have to find some way to keep the toucans from eating the duck food. Otherwise, they would most likely do ok with ground dwelling ducks providing they had plenty of perch area and that your climate is warm enough.
Toco toucans are a popular "beginner" toucan. I don't really consider any toucan a beginner bird because their diets can be quite tricky. I can't see where you are from (my phone doesn't reveal locations of BYCers) but generally toucans are expensive. The last person I know who bought a young weaned toucan spent $10,000 for it, but they can be well over $15,000 depending on the species. If you live in an area or country where toucans are more popular, they may not be as expensive.
Of course, if you have the money to spend, more power to you! Just make sure you do lots of research before getting them. They are not a very forgiving bird when it comes to mistakes. Especially with diet since they are so prone to iron storage disease.