We took the reverse action and started lowering asking rents until they moved.I suspect the reason that one property of yours turned quickly is because your asking rent was very favorable vs. local competition. 

You may FEEL that they are but your expenses may go UP at the same time as rents need to be LOWERED!

I would not put so much on an appraisal report.A number of reasons might be the answer for this lower appraisal report:1- What city is this property located?

Local banks typically offer lower interest rates but might require a solid track record and detailed financials.

Which is why I pay more, for less cash flow in highly desirable areas.In high income areas, rent is a lower proportion of income so therefore your tenants have a higher capacity for paying higher rent because rent is less than 20% or even 10% of their income.

You’re able to learn the basics of a real estate investment with lower risk and build equity at the same time.Because you're in the military, you'll be able to enter a property with 0% down which means you can leverage your money way more effectively. 

I would just take into account that a lower down payment will mean a higher monthly payment so be sure to run the numbers conservatively in order to ensure your STR revenue is able to carry your monthly payment with this higher mortgage cost. 

I would like to have lower monthly payments should I make a big lump sum payment towards my principals and ask my mortgage company to adjust it or refinance it or which one is the best ? 

Seems like it's in a lower end area so if it is filled you will have tenant issues and turnover cost.

This implies residential units can be built at lower costs and provide better return. 11) adding an ADU to SFH can make the SFH fall under rent control.