IMHO the extra bathroom is worth the trouble, especially with all the secondary reasons you mentioned.I realize that I'm not likely in the demographic you're aiming for, but hope this is still helpful. 

She is elderly and stated that she would like to aim for a 5yr loan (30yr amortization) which is fine with me because adding the two additional units will increase the overall value so then I can refinance out at a much higher ARV.

For example, property managers usually aims to minimize vacancy and handle maintenance, they don't necessarily care about the actual profitability of the property, whether it was a good deal when purchased, what's the tax implication if you were to sell a under-performing property, but these are important for self-managing investors to track in order to succeed in the long run.

Are you looking for long-term generational wealth or just some side cash to supplement your current salary?

Price wise I want to aim for properties that are below 290K and that could still net me $200 /mo with no more than 10% down.

What’s the minimum cap rate to aim for for MFH 4-6 units.

Aiming for "$100 per door" or "$300 per door" is completely arbitrary and meaningless.Instead, focus on the return on your investment.

During that time my wife worked two jobs to supplement what we had saved up until my first commission check arrived!

Hi, my recommendations would be if you are planning to live in the property and then rent it out when you buy another I would aim for the townhome in a prime location.

This book is aimed at providing the reader with a comprehensive guide to the accounting and financial aspects of real estate investing.