We're based in Tampa and, in addition to personally investing, I own a mortgage company that provides financing for tons of investors.

How do you finance the tear down do you add it to construction?

It is much better to have a reserve fund and add it monthly.

The family viewed the house, loved it, and requested that I install satellite TV and add it to the costs, which I did.

That said, make sure you're accounting for all expenses, like maintenance, vacancies, and property management, to ensure the cash flow is reliable.

I've seen some people house hack a single family home by renting out the rooms, but keep in mind that traditional lenders would not be able to use the income from renting out the rooms (known as boarder income) towards additional income on the application.

What zoning code could I request a zoning variance or rezoning that would allow us to have the 2 livable units on parcel, one primary residence and one additional living unit (known currently as ADU)?

Just ensure any updates comply with Pennsylvania laws and are handled transparently.

I should have ran the plumbing for it even if I didn't plan to add it.  

Give them a 60-day notice, then charge them a prorated rent for the additional 20-day extension.