As an investor you have less stress, you don't have to where a yellow or blue blazer, no need to look for the balloon in the air and don't have to pay dues, attend meetings, meet a quota, do a coop with agents who take part of your commissionJust think no floor duty, no driving customers around to look at houses,  waste your time and gas. sap your energy and leaving you only to buy a property from their brother in law who just get their licenseOh YES, the freedom to make all the money your are worth, no need  for the hassle of finding listings, prospecting, floor duty.......oh the freedom that an investor has, oh the pleasure of sleeping late, making creative offers, doing subject to existing financing, delayed settlements, collecting assignment fees.....oh the sweet freedom of cash flow and free time.

I was just told that my mom's debt to ratio was too high, meaning that the current mortgage of her home plus the mortgage of this home in comparison to her income is too high.

I have the 30+% down and a credit score of 760+ with minimal debt (few hundred dollars).    

I've seen a video on youtube froom "Commercial Property Advisors" saying that it is actually better to buy a 5+ until as opposed to a 4 unit building because then the loan is commercial and the property cash flows factor into the evaluation of the property in underwriting (in addition to you still being checked out for income, assets, debt, etc.), whereas with residential, you can qualify for residential on just your income and assets alone, no evaluation of the property.  

Also, we don't know what your gross monthly expenses (including debt service, OpEx, CapEx, insurance & property management fees) would be on those properties, after pulling the equity out and/or after the refi.  

If you are going to do that just get  a 4 plex with long term low-fixed debt for 30 years with 20% down.A 5 is above getting a good loan on and too small for the better commercial loans. 

I don't like my clients to be mortgaged to the hilt and in debt up to their ears (ironic considering what I do, I know), so I always give a little talk about how *guaranteed* ROI on paying debt down early is exactly equal to the interest rate on said debt.

Hire a RMLO or Mortgage Broker to be able to look through a credit application and a mortgage applicationLook at debt to earnings ratio or DTI, look at credit, look at length of employment, look at length the residency in the area,You need to sell to the tenant buyer the neighborhood and for them to want what the house offers the family,  to be able to step into that opportunity to get out of that apartment or rental property. 

Debt for cars is bad debt.

Based on the info you provided, it sounds like you have around $100k to put down while carrying $300k in debt service per property.