I am one for symmetry. My husband laughs at me, cause I need balance, in all aspects. He says I even have to have equal portions of each food on each plate when I serve.
Anyway.. I would probably go with the Hydrangea.. IF I were thinking as to what would be 'perfect'.. but seeing as how it could die as well, due to the natural needs of the species.. I /might/ lean toward the other little bush you mentioned. Since your hubby is adamant that no shrub shall grow on the North side, you must do what you can with what you have I suppose. So, I say go with the Blue Mist shrub.. no it won't match, no it won't be symmetrical and perfectly matched.. but it will thrive, be healthy and beautiful. And that will make you feel good.
I hope I have helped some.. if not, totally disregard this post!