Worked with architects, surveyors, builders, agents, and attorneys.

Also, first thing you need to immediately do is file for a use permit for a two family dwelling, I’d suggest hiring an architect to do it as it’ll only cost a couple hundred bucks and you don’t need plans.The code also just changed requiring all rehabs in which you are not and owner occupant to have drawings in order to obtain permits, so you will need to have an architect involved

He is one of the pioneering architects of Architect as Developer (A+D) and is one of the most successful at it.

Make sure you understand the current zoning in the property and whether the town/city would approve a quad, unless your architect already completed that step.

In my "9-5", I work on a lot of as-built surveys for architects/home owners adding ADU's.

Also you might have to renovate both apartments electric to make bills split as well as water and gas.Also don't forget the towns permit fees, architect costs + the acutal cost of the property etc.

You will likely still have plenty of red tape to deal with between the architect and the City permitting process, etc.

Agreed with @Cathy B.You can also reach out to an experienced architect or engineering firm. 

This doesn't include soft costs (architect, permits, etc.) or site work (septic, roads, grading, etc.) if applicable.

Hey Josie, I am an Architect, and have done a fair amount of work in the City of Atlanta.