I have used this grain many times to make a great hefe:
60/40 what/ barley mix by Breiss
I've steeped a pound of honey malt in it before and I recommend that to try as well - delicious.
But then I went AG. And I will not go back. Pilsner malt with wheat malt mashed in and some rice hulls. It's so much lighter tasting and MUCH lighter in color......IMO what a hefe hould be.
Alas, we come to the lat part of your question...YES!!! It's definitely about the yeast for a hefe. The other part is not AS crucial (grains), but it does make a difference and that is why I make beer - to make the BEST product possible. All the little differences end up making one very big sidderence - pour, nose, color, taste.
Being Dealt (kegged): Carbed Crystal light lemonade for the boys, Delta Bravo IPA, Applewinder
Primary: Climbing stout
Primary #2: ESB
Big Blind: Pucker Bitter
Tasty Remembrances: White 'N Nerdy, Dynamite Red (Hop bursted), APA, The Bonaduce (irish Red), runners stout, ridgeback brown,
from my big ass computer sitting on my floor