You also seem to be confusing Entities with contacts and merging their usage. For example, if you are hiring a company to do work for you, the individuals are not entities, they are "contacts" which is a general class of people who work for a company you do business with. If you need to know Joe is a plumber, then you can add something like that to the "contacts" section. Probably a child table because people can have multiple skills. A contact could be the owner, a sales person, or a worker that will be sent to your site to perform a task.
