Rebuilding after Life Happened – 582 now 629

Hey guys — Like the title says, life happened, had a credit score 0f 778 that dropped to 582 after losing my card and charge off card with Capital One – balance on card 11k. I'm now paying off this card monthly with a payment plan after being sued. Plan to call law firm by end of August to ask to settle for a lump sum. For now I have a secured Discover Card ($200 CL), Mission Lane ($1300 CL) and just got approved for Navy Federal More Rewards American Express Card ($500 CL) – thinking if its best to get rid of Mission Lane now or hold on to it? I don't have an annual fee with any of the cards.