In this case, would it be wise to get an additional loan to cover the remainder of the property or wait until I am able to save up enough money on my own? 

If additional info is needed please ask.

I am adding an additional room.  

And with the $50,000 from those two houses I'd buy a third house and get $25,000 down with an additional $500 a month cash flow and keep doing those until I ran out of cash.

Free cash flow will be split 50-50 once a yearIf additional funds are needed for cap ex, we each put in 50-50All equity build up will be shared 50-50, including; loan pay down, appreciation at time of eventual sale, and any 'cash out refinances' as we goPMPs original capital investment down payment will be returned to them WITHOUT interest at time of eventual sale or buying out of one partner or the other. 

Additionally, has anyone done a hard money loan?

Whatever that number is, ask for it in the form of non-refundable additional earnest money on the property in return for extending the contract.

If you want to take on additional members down the line, that will also affect your decision.

These are professionals with additional training and a stricter code of ethics.

I don't have experience with college rentals, but I would say get first and last month's rent in addition to the deposit up front.