or is it still possible to transfer the home to an LLC for asset protection with a quit claim?   

I’m unsure if HEL or HELOC or selling the rental, doing 0% balance transfers makes more sense, or a combination.  

I don’t have an immediate need for the equity transfer but it seems like the right thing because mobiles are so hard to leverage and I don’t want this new property using up all my equity indefinitely. 

But my background and experience is in Business Development, and Marketing Strategy in close integration with sales, so I figure I at least have some transferable skills that'll allow me to make the most out of property as an asset class.

Lenders may or may not let you transfer the title over after your purchase.

Remember that if you later take over and manage it yourselves, you'll need to start a new account from scratch - your previous reviews with that property manager won't transfer.

Considering our options - if we opened a Delaware LLC could we purchase a property under or transfer under if the property is purchased in CA? 

I'm a huge spreadsheet nerd too :D You could even just take the line items from Deal Check and transfer it to your own spreadsheet just to make sure you're not forgetting anything.

transfer it to the next property or leave it be and keep renting it out. 

Land banks, the city actually owns the property and can transfer it to you after the application process I mentioned above.