Ferment it cooler, 62-64. Banana is awesome in hefe! But a nice balance of banana and clove is definitely nice. Hacker-Pschorr hefeweiss is a nice one. My usual benchmark is Weihenstephaner, but that one leans more towards banana than clove.
Pretty sure mash profile has nothing to do with the ester profile you'll get from the yeast.
Depends how you like your hefes. You like them tart and crisp or round and soft? I prefer them to be round and soft, so I typically use a fair amount of chloride in my water and hardly any sulfate. Maybe 60-75ppm chloride.