My question is related to the following technique:
How do they mix real characters with animated characters?
Except that instead of having a real Dick Van Dyke during all the scene, an animated Dick Van Dyke is superimposed and replaces the real one. Same with the wooden gate: a real one with lots of details and color shades is replaced by an extremely simplified gate with minimum shades and traces, while keeping the resemblance to the real thing.
I need to hire a professional animator to do something like that, but I do not even know the name of the technique. It is often used in TV commercials.