.- No more then 3 yr option term, ideally 2 yr max.  1 yr is optimistic and any shorter it must be "GURU" talk. 

Honestly i have no clue which angle he was ultimately trying to go at, but it sounded like he works with a lot of investors who own real estate that produce more deductions than they have in income to claim on taxes, the point he kept repeating was that you can calculate how much income on a property could maximize the usage of all your deductions, then either pay down to this point and maintain it, or refinance the property in a shorter mortgage to gain income and bring the level back up to this level every so many year or after paying it off. 

Any future financing (i.e. your Refinance loan) would now be a Commercial loan with different terms for amortization, Interest rates, and shorter loan length with balloon payments.  

I could also pay more monthly cash out of pocket as my finances allow it but I'd prefer create cash-flow and put that extra cash into other savings or investments.Any other pros and cons of shorter vs. longer term HELOANs?

Shorter is better for people to spell.

Longer projects I like to set up a percentage system with them and shorter repairs remodels the job should be done quick enough that it wouldn’t matter.

I like modular home because of relatively shorter and firmer timeline and fixed budget where contractors don’t hold you for ransom but this works only if you know the design that is going to work.  

10-15 days would be a reasonable amount of time,but in higher demand properties a shorter time is advisable

With HELOC funds my preference also would be for it to be a shorter term play (less than 18 months)  vs long term.

Can anyone guide me on where to find this information on whether it's legal in Texas.Thanks Yes and No.Generally, you can do a Lease Option in Texas that is 6 months or shorter if it has a bank loan on it.