Anything other than criminal background checks, credit checks, eviction and court records, employment history and rental histories. 

My husband and I are looking for recommendations for sites that do the tenant background screenings for you (criminal history, evictions, debt in collection, etc...).

The site is treasure trove of hand on experience and also many professionals to get where your real estate goals are.

Certainly the margins are decreasing due to both increased government regulation and market saturation.But professionals like Neil Collins here in Portland, who self-manage effectively, and can deal with government wonkage effectively still have profitable margins.  

Here are some background information to help with his questions. 

We had tons of interest from small families and young professionals because of the size of the home, freeway access, and proximity to the local university and hospital.

Give some background and update your profile like @Rick Pozos mentioned.

Do you suspect the lead pain or has it been professionally tested?

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

Most professionals are time poor so you can bring that to the table and get paid to learn.