It's a waste to just put it in saving so... is it better to put it into the duplex (the 40K is the 20% down on a commercial loan at 5.25% 20 year) so I have even more equity or roll it back into our original property.

Refi cash out, roll heloc into loan.

How do I use the equity I have while having terrible credit, so I can get things rolling and out of this stuck mode?

If you'd like an introduction to a lender to get the ball rolling I can help you with that.

My plan is to roll over an existing Roth, so I can start using its funds for REI and doing private money deals.

You could easily roll it into a couple more rentals as opposed to the original one property.

I’m just giving my insight and trying to help you decide what you are after... with that said, if your rolling on it... if it ain’t broke don’t fix it.... 

Lender (Owner Carry) rolled entire amount (including down) into loan once the roof was discovered to have potential problems.

Hello,I have a couple off market properties in Oakland that I see that look like potential deals, however the finished square footage on the tax roll does not equal the current state of the property.

If you're Warren Buffet or Jay Hinrichs, you can roll the dice and probably win more than you lose.