Financing

I am a newb here although lurking for years and I am finally ready to start the credit repair journey. I have dreaded this day but burying my head in the sand has not worked out for me at all!
 
I do need some advice on what to tackle first. 

Can someone please advise me on what to do with my unique student Loan issue. I took out a loan around 2006 with Salle Mae to pay for school but later found out that I could not get the funds due to academic issues. I had to withdraw the previous semester due to a death in my immediate family. The school never dispersed the funds to my account and I did not sign a check (we had to sign the check back then before the school would disperse funds). For years I thought that the funds were returned to Salle Mae until one day I pulled my credit report and found out that the debt was still being reported. I then filed a dispute with the credit bureau and the debt came back as accurate so I contacted Salle Mae/Navient to verify the debt. They could not provide proof of the funds being dispersed and told me to contact the school. I have emailed and called the school and they have no record of the debt being dispersed on my ledger(because it wasn't!) and just stated that maybe it will show in an older system. As of today this debt has been sold to Navient and I am paying on debt that I do not owe! I have to fight and get this removed as I am not getting anywhere with the credit bureaus, Navient, or the University and no one can prove that I owe the debt. Navient did send me a promissory note that was signed but the funds were never dispersed. I couldnt even qualify for the funds at the time as I did not meet the academic requirements for dispersement. Please help me! 

I'm looking for input on what cards to app for. My bk7 is off of my EQ and EX, and should be off TU any day now. I'm trying to accomplish several things with this app spree.
1. Maximize my rewards on my spending.
2. Establish/reestablish positive relationships with lenders that may be of benefit me in the future.
3. Broaden my base of cards so that, once these are aged, getting a new card here or there will have little to no impact on my AAoA. I am planning to nearly double my current number of credit cards(10). This will hurt my scores significantly in the short term, but should make my credit more solid over time. 
 
Cards I currently have:
Fidelity Rewards
Chase Freedom
Discover IT
USAA Rewards Amex
Wells Fargo Cash Back
NFCU Platinum
Barclay Rewards
Penfed Platinum Rewards
State Department Platinum Rewards
Quicksilver
 
My list of cards that I am considering, with purposes in parentheses:
Citi Double Cash (reestablish a relationship with Citi while giving me another 2% option)
US Bank Cash+ (5% categories)
Amex BCE (3% at supermarkets)
BOA Cash Rewards (3% category)
Amazon Prime Rewards Visa (5% at Amazon)
Capital One Savor One (3% on dining and entertainment) (I am already getting 3% on dining with my USAA Rewards Amex, so this one may not be worth my interest)
State Department Cashback Rewards Plus (another 2% card with no redemption hoops, plus cell phone protection, extended warranty, CDW, trip cancellation)
USAA Cashback Rewards Plus Amex (5% cashback on gas)
Chase Freedom Unlimited (Considering this one only for the $150 bonus and to get another Chase card before I go over the 5/24. I really don't see any use for it otherwise. The Freedom Card which I already have is their only card that seems particularly useful to me) 
ETA: Looking at the Chase Ink Business Cash (5% categories +$500 bonus) I'm just wondering what potential issues there are with using a business card for personal expenses?
 
I would appreciate any suggestions of other cards that may be useful, or input on the usefulness of cards I am already considering.
 
 
 
 

An old CapitalOne credit card was charged off. It went to collections and the collections account appeared on my reports. The original CapitalOne credit card disappeared from two reports but is still on Equifax.
 
Do original creditor accounts that are charged off usually stay on your report after they're sent to collections?
 
Is there any way to get the original charged off account off of my report? It seems odd that basically the same account can show up as two negative items. If it can come off, can you please help me find some resources to help get it off? I found this article but it doesn't help much: https://blog.credit.com/2012/08/credit-report-double-jeopardy-means-double-damage-61199/

Back in July I put 100k on various credit cards to invest in a venture.  Was supposed to be paid back by end of Nov but ran into a few pitfalls and am now looking at Apr 1.  I currently owe about 55k . . I have 125k in available credit 131k if you include Walmart. My experian also has a 24k authorized user card so it lists available credit as 155k and is my highest score .
Nfcu 25k /34k limit
Amex 7k/25k limit
Boa 19.5/40k limit
chase 3300 , they closed my card because of my activity , it was only 2 months old.  This has 0 pct for the next 15 months.
I also have a discover card that I pif that reported 980 last month and has 1300 on it this month.
 
Current scores are 720 EXp, 704 Eq and 698 Tu
 
Would like to get my scores above 740 by mid January as I will be financing a 2017/2018 used car and want the best rate.
All cards are currently paid above minimums for January and i have an additional 10k minimum and possibly up to 15k to use for payments.
 
Question 1.
Is there any advantage to not letting Discover report.  I can push that 1300 off till Feb 6 without interest.
 
Question 2.
My EX only dropped from 714 to 709 when Chase reported it was closed.  Reports were 7 days apart, so is it advantageous to 0 that out even though I have 0 pct and am paying 150 pct of the minimum monthly.
 
Question 3
 Before taking into account the auto financing I had been attacking my BOA card because that was the highest rate and NFCU the lowest.   Will i get a better bang for my buck if i get my NFCU under 50% vs paying down BOA.
 
Question 4
 the last month I have been turned down for CLI from Discover, and my 2 Cap Ones based on my high utilization even though those are 9 balances.  I also have a 6k limit Pennfed that i got in August before all these reported.  It is 0 pct but i have not transferred anything because of the low limit would it hurt to transfer 2900 to that card or  just leave it alone.  I also have not asked for a higher limit because I dont want to screw up and get that card closed.
 
Last Question
In my Boa online they have been telling me that I have a special offer for a 0 pct free balance transfer offer.  Is there any downside to applying for that .  I have not seen any talk about Boa special offers if they usually get approved or not.
 
Thanks for any suggestions.