You don't need a business entity just yetm what you need is a business with paying customers (tenants).

They don’t sell direct to customer

I like using customers/subs on rentals.

Your roommates should be you main concern right now, they are your only customers.

I have been thinking of getting into new custom homes and trac homes.

This one ons walnut and white oak. 

Insightly is easy to use and adaptable to customizing.

If you have custom data like direct mail, cold calling lists or texting lists you can upload this very easily to Facebook and use that as targeting points rather than trying to go broad or find targeting through interests. 

They can customize a search for you for multi’s

Repeat customer with a specific loan agent?