Having a project manager can improve the construction speed, design quality, and business relationships, just as a general note.

I'm worried it's this investor bubble that's all just gonna pop someday.

Buy a property in this city within certain designated areas3.

I would use that to buy bandit signs, books to grow your knowledge, and design a direct mail marketing campaign.

Although I've never been involved in the real estate industry (work in financial services), I come from a family that owns a 3rd generation design-build company so I feel like real estate has always been calling my name.  

While I think you were using it generically, SFH is not a zoning code designation in San Antonio. 

Be cautious though, every bubble eventually pops. 

Web designers are usually pretty expensive for a small business that doesn't have much capital.

What are the costs for a 1st floor rehab and a 2nd floor add, knowing adding a 2nd floor will all need to be designed, permitted, and at least some structural work ?

They have designers (free of charge) that will create a graphic design of your project.