Thank you!
People's appearance is completely random and not related to their interests at all, though it would be a cool idea to have them be linked. Advertising increases both the number of customers in the mall, and also the percentage of those which have a particular interest (e.g. "influencers" will attract more people interested in fashion). However, this was a relatively late addition, so might not be balanced quite right!
I agree with the idea to add a door, too. Thanks for your feedback!