I often sub about 1/2 of the white flour in a recipe for whole wheat flour. The end product is heavier, but healthier. For these buns, I think you would be happy with the result, as they are quite dense, in any case. Make sure you use the right amount of yeast!

As for the pudding, I checked the recipe and I see that the pudding is prepared according to package directions. As this is the case, I think you will have similar results if you prepare non-instant vanilla pudding, and use the same amount in the recipe. I am not sure if non-instant and instant produce the same yield, that is my only warning.

I hope this works out for you,

Carolyn!

p.s. might try it myself!