Recently several of my investor clients have leveraged equity in their primary or investment properties as down payments for purchase acquisitions by obtaining a HELOC or fixed rate second mortgage. 

Definitely check in with @Joseph Chiofalo for Jumbo second home and investor loan products, we just had an unbeatable rate and appraisal waiver here on the coast. 

Also not sure when you bought your primary residence, but most likely rates have risen which means your payment would go up. 

or any recommendations on which is the best Bank/lender to get one with the best rates? 

I have 3 options.1) Cash out refinance with above 7% interest rate.

You would never ask an attorney to lower his rate for doing his job and telling you what to expect. 

"McAllen was recognized as the third safest city by SmartAssest.com, which analyzed a core set of common safety factors, including the following five metrics: violent crime, property crime, vehicular mortality rate, drug poisoning mortality rate and the percentage of the population engaging in excessive drinking."

Look on Vrbo and Airbnb and see if bigger houses are booked at good rates.

This could be risky for them if you already transferred money out of your account or closed it.

So in my case, we selected June 1st - June 29th, adjusted the minimum stay to 2 nights for that period, and upped the rent for that period to STR rates.