The roof will outlast the building.Biggest PITA for me is getting a descent looking over hang on a roof edge 50' long with no eavestrough to hide it.

I'm hoping that my tax due to IRS will be about 50% lower than if I were to have not split the proceeds evenly between 2 properties. 

Same general rules apply in that the assessment value needs to be there for the property as well as your general credit history. 

Near college. 50 pads developed. 

I made an offer on a house and because I am doing 50% financing, the owner offered to lend the other half himself and be paid over the next 30 years, at an interest rate lower than what the bank is offering (albeit, not much lower).

I don't know all the rules regarding this but definitely ask your CPA if you haven't already. 

The property features off the street 3 car garage I will include for $50/Mo. 

Found someone willing to invest the downpayment, I put the loan in my name, and we split everything 50/50 after. 

This will not trigger the due on sale clause as Fannie Mae changed their rules on that a year ago to now allow that?

Yes some landlords do the first $50 thing.