@Ying Lan we are one of the biggest wholesalers in Tampa Bay with 2 brokerage offices, many agents in different counties, a designated acquisitions and sales team plus property management and a construction team.

The biggest issue you'll face is finding a lender that will 1) do a cash out refi for such a low amount (most won't go less than $50k), and 2) do a HELOC on an investment property. 

Not to scare you but it is probably the single biggest problem that can kill your deal.

I am also considering trying to find s partner or private lender.

Your biggest "investment" mistake at the time was: paying full market value.When you only rely on future appreciation, it's always going to a long, slow slog.Which is why I agree with @Scott Bowles urgent advice to you: Sell!

One of the biggest downsides to putting it in a trust is that trusts pay the highest individual rate around $12,000 of taxable income.

It's one of the areas biggest developments.

The biggest question you have to ask yourself is how will you sleep at night?

You might be able to get a cheaper loan than just FHA type loans (biggest impediment to FHA loan is that mortgage insurance never goes off). 

But in the end scale is the biggest difference for me of why you would do MFH over SFH.