Would those other properties better help you reach your ROI / investment goal?

My goal is to keep my mom in her home and to minimize her monthly payments.  

Rarely is that rate bump worth that LTV bump IMO. 60% LTV is actually the Fannie sweet spot, if stopping there will not get in the way of accomplishing your goals.

, What are your long term goals?

Have some guidelines on what you are looking to buy.Write out your goal that you want to achieve with your purchase.  

I definitely did not want to backtrack on my offer and lower less but after physically inspecting the property and the neighborhood it was located in, I realized that it wasn't ideal for my investment goals.

What do you think is a realistic goal given my limited income and age?

That's my goal and desire, but finding listings that are remotely close to the 2% benchmark is extremely difficult.

Longer vacancy means your 5% vacancy needs to be raised to something like 8% to account for longer vacancy between tenants. or you can rent for 650-700 and get it filled faster. but the point is you have an agent admitting that 750 is pushing it and would deter many applicants from considering.

I think it starts with your goals.