It's easier to reach a settlement once the account is outside of the SOL because they really have no recourse to force collection any longer. I would definitely attempt a settlement on any of the accounts that are outside of the SOL. Don't attempt though until you have the money to pay. There's usually a deadline on the settlement offer.
As far as the secured card of your wifes. Even though it's only a $90 balance, it's a high utilization on the card because the credit limit is only $300. She would be better, score wise, to carry that $90 balance on the Cap 1 card that has a $1000 credit limit. Keeping utilization down to less than 9% if best for scoring. It doesn't mean that you can't use the card more, it just means you need to make payments before the statement posts so that the balance reporting to the credit bureau is lower.
I would hold off on any additional credit card applications right now because your goal is the car loan. You have 3 revolving accounts that will be on your credit report soon and that should be plenty.
