Recently I was working on a house and the inspector call out several issues regarding a deck on the back (among other things), I decided to get a structural engineer just to get a second opinion and the engineer put a report together explaining why the inspectors was incorrect. 

Most of the other “financial engineering” is bunk.

If the walls you want to remove are not load bearing, you don't need a structural engineer for this project.

I would inquire to local environmental engineers and even try and speak with the gas station owner.

Thus far we have demo'd the property, and we are waiting on the architect and engineer report to decide final design.

The full blown engineering report is more likely to succeed in an audit, the historical average has less probability.

I currently work for a multifamily construction company as a Project Control Engineer.

It didn't work out that way, but I did manage to make it through engineering school (I was the first in my family to go to college and had to be my own role model).

Who do I call to create a subdivision, a surveyor or an engineer?

If the lights stay green, you'll need to engage at a minimum, civil and structural engineers.