We are looking for a company who could maintain the loan and report it to credit bureaus to help improve their credit scores. 

Basically, you get punished by the credit bureaus, if you make a payment on an old debt. 

You can at least prevent/reduce the credit card letters by asking the credit bureaus to stop selling your address and by putting your name on the direct mail associations "do not mail" list.

They are saying your request is cancelled and you owe us $80.Now I'm concerned about the legality of the document and if I'm obligated to pay more than the deposit in this condition when I eventually agreed to move in on the decided move in date.I'm ok paying them to avoid the situation of them reporting me to any Credit bureaus for $80 but I'm curious about the legality of the document.

@Ian Whiteman I believe that for mortgages you have a 30 day window where you can have various inquiries that will only count as one on your credit, because the credit bureaus know you need to shop around. 

She pays most accounts off monthly, but is having a hard time finding a card that actually reports the authorized user to the bureaus. 

That judgment will be reported to all 3 bureaus automatically.Start now, don't linger any longer. 

That one single person who has ever been accurate did so by going to the FICO website, he clicked "show me the scores used by mortgage lenders," paid $20, and I ran his credit on the exact same day & the exact same number for all three bureaus (which meant it was a waste of his $20 in retrospect).

If it's a bank or other institutional lender (a company whose business is lending), you should expect they are plugged into the credit bureaus and will report your payment history there.If your lender is a private person, like a friend or family member, or maybe a local person who makes a few loans a year, I would assume they are not plugged into the credit bureaus and the loan won't show up on your credit report.Keep in mind that if you apply for other loans, and they ask you for a schedule of real estate owned and mortgages you're responsible for, and you omit a property and/or private mortgage from that listing, you'll likely have committed fraud by saying that you're submitting complete information about your financial situation but intentionally omitting something.In other words, a loan/property may not show up on your credit report, which means a lender you're applying to for a mortgage may not know about it, but that doesn't mean you're not required in the application process to list it anyway, and it does mean that if you intentionally omit it, you're probably committing fraud or breaking some other law(s).I would assume that the loan could show up on your credit report, and that you will be listing it in future loan applications to institutional lenders, and behave accordingly.

My friend just got a consolation loan from some third party though credit karma to pay off his credit card debt, then since most credit cards report to the credit bureaus usually weekly, within a week his credit score shot up to 740.