Sounds like a 5050 partnership and marriage since going into the deal as buy and hold.  

I'm kind of at a crossroads because the woman whom i'm related to by marriage said I need to find a way to get side A completed soon or she wants to walk away from it.

I was assuming the "We" means your significant other but if it is a partner outside of marriage there could be some reasoning to have proper paperwork for it. 

While fixing it up will give you sweat equity, the stress renovations can put on a marriage with kids can be very harmfulJust my 2 cents

Are there any lending companies or hard money companies that lend with a 607 credit score (marriage)?

These are the opportunities created due to changes in family situations, marriages and divorces, job losses and gains (on an individual level) and so on and so forth. 

My wife would like to set up a single member LLC for her private practice as a marriage and family therapist.

I WOULD PAY FOR HIS SERVICES.Now, if a potential partner shows me I can do more deals simultaneously, and/or save money on projects by doing them at cost(no overhead), as well as mentor me in aspects of construction/rehabbing, then it might be worth partnering.Please think long and hard before you partner with anyone....just like marriage :)

There is much more to it than assessing a value of your collateral.You should also understand how "life occurrences" play on your loan, incapacitation, incarceration, marriage, divorce, bankruptcy and death.

He can barely get around due to his condition, I felt kinda sad for him he can't read or write.They have 6 kids together, 9 in total, 3 of which are from his late wife's previous marriage.