Now, with all the reading and self-education I’ve completed, I am somewhat aware that focus should be on specific niche.

I suggest educating yourself in the different Houston submarkets and target the ones that fit your investment criteria.  

Rents can be increased probably 100-125 per unit.This is acceptable to me.However, buyers refuse to show any proof of income and DD period is over tomorrow.

I know I likely wont see a whole lot of appreciation (if any) on properties in these areas but part of me feels like there is some real potential to make some money over a 10-15 year holding period, especially if I can knock $10-15k off the asking price.

I don't think AirBnb would work since I won't be there to oversee, and there's too much risk of long periods of vacancy.

I have a passion for real estate investing, and i am in the educational phase looking to start purchasing property in the near future.

Check the Get Rich Education Podcast, there is a lender that frequents the show named "Chalee" something (that is 100% spelled incorrectly). 

The Notes are for a period of 13 years at 9% with payments of $350 per month.

Educate with Podcasts, Books, Webinars, absorb as much information as you can and focus on a specific niche.

However, if this is simply a case of spending a little less on personal lifestyle choices now during a cash poor period while you complete a couple of rehabs, I say absorb the lifestyle pain now and enjoy the profits down the line.