The house has a flat roof.

The leak in the roof that we have had since October.

You could get a thorough inspection by paying a few hundred extra to get things like a sewer inspection or drone roof inspection. 

the roof etc too right ?

If you lack the development expertise you're probably going to need to attract a co-founder that knows this side of the business well. 

Call those people up and offer to do their homes in exchange for planting a sign in their yard, similar to the roofing or painting signs you see after someone gets a new roof or paint job.

Also if this is a double net with lease coming to and end in 5 years likely tenant will want new roof, parking lot recoat, etc. to extend the option even if it doesn't say so.Usually I get on a call with clients and go over their goals to find out whether a property might be a fit for them or not.

From those experiences I have learned what I am most focused on in terms of inspection worries, which are mechanicals (HWT, Furnace, appliances) and structural/roof issues.

I.e. roof repairs

The home needs some tlc from new flooring, half a roof, paint outside and some other cosmetics.