Duplex Conversion (Montrose Area) – Height Limits, Parking, Retail Restrictions?

I'm considering buying a duplex in the Montrose area. It's on a 5000 square foot lot with a one story living area. I'd like to convert the property to a quadplex that includes a bit of retail space on the ground level, since it's on a street that gets lots of vehicle traffic. My plan is to duplicate the existing floor plan on top of the existing structure to add a second and maybe even a third floor. Before I pay to have an Engineer inspect the existing foundation to see if this is even possible, I'd like to know if the City of Houston will even allow me to do this.

Unfortunately, the Ordinance Code is about as clear as mud and written in complete legalese with references to Urban vs Suburban Areas, Major Thoroughfares vs Streets vs Collectors, etc. I can't seem to find information confirming what guidelines would actually apply to this property.

Is there anybody here with expertise in this subject area who can shed a bit of light on this?

My main concerns are any parking requirements, building height limits, limitations on the retail/commercial component of the property, and issues with paving the lot.