I agree with André,
if fields are worthless, leave them, don't provide them data at time of upload. may be those can be used to anytime in future. by deleting fields you are limiting your entity.
In fact, these fields are related to generation of InventDimId, and its not must that those will always be useless.
for your other point if StyleId is missing, you can add that, by modifying underlying query and adding it as part of existing logic which is responsible to generate InventDimId