Would allow for more flexibility to utilize Big Shelters or creature specific housing for fulfilling orders.
Big shelters should count for fulfilling orders that require you to build shelters. Or maybe they could require you to have X number of people housed or no one without housing.
I don't think they need changes. Orders aren't for flexibility - they are to struggle. This is correct for any orders. You may produce goods you don't need. You may build shelters you don't need.