These questions are specifically in reference to Single Family Homes, Luxury, Duplex Rentals, Small Multi-Family 6 to 12 units and Long Term Corporates/Company Rentals - we do not do Short Term or Month-to-Month Rentals.

I bought my first rental duplex and one very important feature was that it came with a 2nd lot i could build on in the future or sell if i needed more cash during the renovations. 

In PA, basement habitation is not allowed if any basement wall is below grade or if the basement exit door to the outside is below grade (PA 6400.81).

The land is Residential Agriculture but I wanted to try to build a duplex or expand the number of bedrooms in the unit.

A duplex in one state, and 8 units (3 single family, a triplex and duplex) in another. 

At Neu Real Estate Group, we specialize in vertical development, particularly new build duplexes in the Indianapolis market.

but in the short term (2 years), we have enough cash and plan to buy a 4 unit and enough equity in my first duplex to buy another 4 unit.

In Mass, that means that all components are double-wall, non-corrosive (fiberglass). 

It is an older home, and would be hard to move walls around to make space without basically taking the whole house apart.

It is a duplex that needs considerable cosmetic work on the one side.