..."First of the year"....However, I started repair last August and by September, by scores went from 524-544 to 620-640 within my first month of repair. So, by January 1, you definitely could be in the 600s.
If you have the money to PIF, then don't worry too much about SOL. Read the second link I gave you. It has links within there for sample letters, steps, etc.
Even if you know you owe the debt, send DVs to all CAs, using the account numbers and addresses found on your CRs as pulled directly from each CRA. Give them plenty of time to respond and keep your eye on your reports. I'd recommend using a credit monitoring system like TrueCredit to monitor changes. For Bureau of Collection Recovery, send them one letter (for same debt) and mention that they are reporting twice. I bet they'll delete both without paying a dime. Send all correspondence to CAs CMRRR. Once they reply, and you agree with them, then offer a PFD.
For the OCs, all you can do is send a PFD. Offer to PIF or if so inclined offer a settlement of a lesser amount. IMO, PIF improves your chances of getting it removed. From personal experience, CapOne and Verizon are going to be an uphill battle. Use the PFDs found in here. I edited mine to removed the timed requirement and I don't send mine CMRRR.
If you have no open CCs or other accounts, I'd probably wait on the OCs. Removing Verizon and CapOne will remove badly needed history. Removing the CAs will increase your score. Once your FICO scores hit in the 600s, then I'd recommend opening some CCs if lacking them now.
If any debt is medical related, then read on the HIPAA process before doing anything.