You would basicly be making the 3rd bedroom into a den since it needs a closet to be classified as a bedroom. I think you are on to something and it might be a good idea for us to think about.

Good idea about combining the closets in BR 2 & 3. I know that the 2nd Br closet door is a pocket door and you may have to change to bi-folds if you convert both closets for the 2nd BR. I think that the 3rd BR also has a pocket door but I can't specifically recall. I think that you'll like the Zinnia design once you see it in person. Personally, I found it hard to really grasp from floorplans and pics. Actually walking through the house really lets you get a feel for it. Good luck with your decision!