Deed transfer and tax implications

[Marko Bukva]

My wife's grandmother passed away two years ago, and we still have her house in San Gabriel, CA. It's paid off, and is currently held by the trust she and my grandfather set up. My father is the trustee and sole beneficiary, and plans to will the house to my wife sister and her.
We want to take out a HELOC on the house to invest in real estate (we currently have two properties and are planning to scale up). We are talking to my father and my sister to see if they would be amenable to transferring the deed into my name to facilitate the loan.
In order to move those conversations forward, I'm seeking more information on:
1. What are the tax implications of transferring the deed? Is there a smarter (tax-wise) way of leveraging the equity in the house?
2. If we move forward with transferring the deed, we would like a way to guarantee to my father and my sister: a) some return from investments made with money taken out of the house, and b) equal shares in the house if we sell in the future, or a buyout path for either of them.

3. Recommendations for CPA or Tax Lawyer in LA County