I suggest putting in at least 4 inches to cap your building and improve energy consumption, At the time of the tear off coordinate renting a blown insulation machine too and you can add insulation from the roof into the attic/crawl space above the ceiling level to avoid interior repairs.

Your scenario comes with a few loan level pricing adjustments.

Ideally the PM I work with will be resourceful, honest and has a certain level of business acumen.

Many posters on here are giving opinions based on various experience levels and particular strategies they have found success with and see value in.Someone making 300k a year isn't living off of the investment cash flow.

Final and most important point, surround youself with people who are very knowledgeable and look at for your interest becasuse I have found in life that most things can be accomplished if creative thinking is done but most important planning ahead and that might, depending on your level of expertise, mean you need to find a few investors or CPAs, or investor groups to hook up with.I am investor and every true investor I have met, actually loves helping people succeed. 

A one-off is ok) - your S-Corp automatically converts to C-Corp, and you're taxed at the corporate level at the corporate rates (you then lose the capital gains rates, personal brackets, etc).

Do the activities in this particular case arise to the level of quantum meruit; ALA the painting?

Decide which level of risk you're willing to take (based on your cash position, your personality, your confidence in your analytic skills, and your life goals), then compare properties until you find one with a risk-adjusted return that's HIGHER than your alternative investment options.  

Is it worth digging deeper?

Additional level of risk and makes it less desirable.