Pls advice, Sounds like you have been presented with an opportunity to help a veteran and increase your rents upon placing the next tenants.

Consider semi-furnishing the space to increase room rental costs and also contact your local university/college housing department, they typically provide students with resources for off-campus housing and you could plug yourself in there. 

Many lenders will charge additional rate increase if loan is under $150K.

You also need reserves for vacancies, general emergencies, etc.so the real take away is that you did not make $27k on those properties for the simple reason that you failed to adequately calculate your expenses.a labeled account for reserves shows your intent and helps justify your deduction.

Your mentor has needs; try to meet them and develop a mutually beneficial relationship.A mentor can benefit your growth, but it's not as simple as one post on a forum full of strangers.

Do you believe 4-plex and apartment buildings would increase your ROI?  

My mortgage payments on the duplex increased dramatically over the last year as well, and currently it is appraised at 720K with 4,100/mo rent.

Due to the current high interest rates and prices, many investors are choosing to increase their down payment to ensure a positive cash flow even in the not so "nice" areas and plan to refinance in the future.

If you sign a multi year lease, build in the rent increase after 1 year and don't go longer than 2 years. 

And hell, don't be turned off by the simple SFH in a solid location.