They can't be made to commute. That's the problem with ploppables. They will "survive" in very specific situations, but residents can't leave them. This is controlled by game files.
This is correct. Personally if I want a certain building to grow, I zone the specific size and make sure all other building styles but its own are disabled. Then I patiently grow and destroy until I get what I want; sometimes I do this for multiple blocks at a time. I do this in cheetah mode, but be warned, it'll make your city hundreds of years old.
I started doing this too, but then there were buildings that didn't appear no matter what! =( I reached 2900 game years and I still can't get some of the buildings, specially the commercial ones. My demand is naturally sky high, desirability data is perfect, and i've checked all the caps. But no luck