At the conventional rates over the last 6 or 7 years I view the loan as almost free money; there is no cheaper source of money for the majority of people/investors. 

I think you are missing the major first step: determine if the complaint is legitimate! 

I shouldn't have an issue refinancing, other than the property not appraising, or, if we have a major down turn at that time. 

To date we have done over 20 flips and had probably more than 20 minor and major disasters including floods, over budget projects, being ripped off by contractors, and even getting sued.I have some ideas on how you can strategically get rid of the debt faster and get your credit fixed.

Also look into credit unions that have a business department, you may be able to get a lower rate than you mentioned.

@Chris Youssi I disagree that any of your top 3 will protect you from a major down turn.

-  If it's a major flip, let's say another of my $50k is added, making the split my $115k and his original $40k, or 75/25 - makes me feel like the original 50/50 is not as fair as what it was when we started.Is a flat "+10%" fair - so at 60/40, it changes to 50/50. 

Get a hard money loan and pay off the majority of the credit cards.

Amazing how many deals get lost because of poor training, education, and simple Math . Most investors go into a deal worrying about the price and cap rate. Lets share an example here: These deal may still be available...

Generally speaking I like to have a majority of 2bedrooms.