@Joe FreyIf you are redividing the property into two units, why not simply put separate electrical and, if present, gas entrances into the second unit?  

The places i've seen has the plumbing/electrical/HVAC so its a fair simple go.I will admit I spend $2000 on cameras, and exterior lighting.  

Best way is to obtain authorizations for release of credit, tax returns, assets and liabilities, then send copies or get several originals to use, mail them  and obtain information directly from the source, this cuts out the chance of fraudulent statements.You also need to underwrite the type of business, what hazards are present, toxics, fire, insurance coverage, competition with other tenants, traffic counts, environmental laws applicable to them as well as your infrastructure being sufficient for tha use.....electrical, plumbing, traps, fire codes, etc. 

Anyone have a recommendation for a structural engineer?

This ALONE is about 50KYou have not even touched electrical, plumbing, painting, roof, hardware, furnace, water heater, landscaping, I seriously doubt the repairs will be 75K

I have all the builders. engineers, etc to make it happen and create upsell opportunities.

Career fields I’ve looked into include Mechanical Engineering, PA, Financial Advisor, Industrial Engineer.

Having a construction and engineering background, I really like to see the quality of construction being used.

To develop a parcel map you need to work with an engineer and then take the map through the city county for approval.Lots of time and road blocks but I would be more than happy to give you some guidance.

Some systems will last a bit longer - electrical and plumbing is typically good for about 60 years.