I know you're not keen on refinancing since you don't want to lose your current rate and you're likely not at the 80% LTV mark, but this path would free up your options and enable you to acquire another multi-family home sooner than saving up 15% down for HomeReady.Also, your current FHA rate of 3.750% will come with life of loan mortgage insurance of .850%. 

I want to make sure that the engineer's company has Errors & Omissions/Professional Liability insurance.

How much are property taxes/insurance?

He’s been in business 15yrs fully licensed and insured.

I've been in the insurance industry for 10 years now and have owned my own agency for 5 years.

With P&I, taxes, utilities, insurance, rehab costs and roughly 30-35% (10 vacancy,10 management,10 capex and 2-5 for repairs) variable expenses.

For example, a medical bill that you thought insurance would cover, but didn't.

Ive worked as a Mortgage Loan Officer for a few years, an Insurance Agent for quite sometime, I also have about 15 years of construction experience.

I have a background in finance and my full time job is in insurance, but have always been interested in using real estate as a wealth building and passive income tool. 

That should help insure some sense of priority and trust to find the right "investment."