I concur with those who say don't use carb heat while taxying. Use it on the ground while stationary by all means.
Try that with an 'ice-maker' and you might see what we're getting at. Mine has cut-out taxying with reasonable power on damp mornings and evenings.
As for the rest of it, don't follow what Bob in the cafe told you he does. His aircraft is probably different from yours. Follow what your instructor told you and (hopefully) the POH also says.
Quite right. But I'd certainly listen to anyone who knew what they were talking about. Unfortunately instructors don't necessarily know the quirks of non-club aircraft.
I've flown instructors in mine just to demonstrate things they may not have come across in PA28s or C172s. Even the handbook may not address some of these areas adequately.
Other owners of your type might be a better bet.