Typically, the initial upfront for the rehab is either cash or a high interest loan (hard money or private). 

I paid cash and roughly 25% of retail value. 

So why not put that money to work and start building up some cash flow?

Lastly, you won't be able to HELOC (or any cash-out equity) and 2-4 unit property in TX while it is still your primary residence.

two families require way more cash and I don't have enough.

I bought my first investment property cash, for $101K.

I thankful for finding this app through a book I have been reading.But I would like to inquire in regard to introducing myself both to sellers and cash buyers.

These sellers paid much less than what the going rate it today, likely have no mortgage or low interest rate mortgage and do not need to push rents to market value to cash flow.They get solid returns at their current rental values, have minimal headache with current tenants and they don't need to do major repairs to get their properties sold for a solid value. 

It depends. all you talked about was the property but financing is more about the borrower, their experience, their credit, the cash available etc.

If you plan to use cash to finance your acquisition and rehab expenses, this will help minimize risk exposure to a certain degree.