Additionally, I have a lot of clients that are private money lenders if you are ever in need of financing.

Plus those storefronts will be difficult to rent (at least I think so) I would be curious to ask why they are vacant, how long has it been since they have been rented and what type of businesses were in there prior.

However, check your doors and windows, if these have become difficult to open and close then you could have a possible foundation issue on your hands.

It is difficult to acquire more than (3) homes using conventional lending. 

Churches in my town use houses to assist those in need and I'm sure you can find some willing to sell.IRA will be difficult because most of the time you are mailing to the "custodian" and they'll probably toss in the trash.LLC's (or other corporations) are up to you.

I have been listening to the Bigger Pockets podcasts ad nauseum for several months now while I work for my father (when I'm not working with clients I keep the money flowing by doing so) and one of the main things that I have taken away from all of the guests is the majorities' response to the question of "what do you think separates successful investors from those who give up, fail, or never get started with investing?"

It is incredibly difficult to manage, control, and has constant turnover.

Only problem I forsee is my work is in west midtown and finding something close to the area may be difficult.

Since you have a 3-unit, it is going to be extremely difficult to get approval for an owner occupied 4-unit in the same area.

ELOC are difficult to find on investment properties and probably will not desire to go above 70% LTV so likely will not be able to help.I understand Texas to have high property taxes.