Totally doable if that sounds like something you're willing to do.If you were looking to go that route, I'd recommend getting a Customer Relationship Management (CRM) software to keep track of leads and follow-ups.

The long term goal is to do custom homes, starting with spec builds.

As soon as you start discussing your business practice and strategies with your customers (tenants), then all bets are off and you run the risk of Fair Housing violations. 

If its a very large property, you may also want to make sure you are marketing to any wedding, family reunion, corporate meeting/team building customers. 

Quote from @Dave Foster: @Jay Hinrichs spot on! 

If the product/contract/service I offer is not suitable to you then I don't want you to be my customer.

They offer flexibility in design and can be customized to include a business space.Shipping container homes: While trendy, these can be challenging for mixed-use (residential/commercial) purposes due to zoning and building code issues in many areas.

Excellent customized spread sheet. 

The software allows me to generate custom reports on my rental income, expenses, and overall performance.

For people reading this - I don’t know the sponsor and this is a general comment but if a sponsor had issues reporting to their customers that should be a giant red flag.