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?

@Damon AlbersSounds like these properties are in a class c area and your manager is not doing a good job vetting themBut this is not out of ordinary for c class rentals which is why people look at cash flow and be like wow but one $5000 bill can wipe out 4-6 months of rental income and properties never make money and rarely appreciateThis is why we do not do lower class rentals as stated cash flow vs reality are typically not close

I'm going to start reaching out soon to a friend of a family member who owns a local PM group with roughly 1000 doors for lower income, just to pick his brain, but I can envision a scenario where if I needed to partner with someone to get my first deal and gain some creditability and experience, he may be willing to assist.

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.

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 ? 

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. 

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

If I have lump-sum free cash, should I just apply it to my mortgage to recast so that my monthly goes lower?

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.