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Welcome to the forums!
I'd suggest reading the following:
Common Abbreviations
Credit Scoring 101 - great for knowing what is in your credit score and to see how your score is impacted.
What Steps Do I Take - great for learning the repair process.
and Example letters - PFDs, GWs, DVs, etc.
For the paid collections, send a GW letter asking if they wouldn't mind deleting.
For the unpaid, make sure you have 100% of the balance saved up and be willing to pay in full. Continue making the payments as agreed, but send them a PFD letter. If they agree in writing, then pay it and they'll delete. But even if they reject or don't respond to the PFD, keep making those payments on time as promised. You wouldn't want to void any agreement due to a missed payment, especially if there was a settlement involved. You wouldn't want to owe more than before.
For your DW, send a GW.
Score increase? It's possible. YMMV based on what was reporting, how it reports, and your overall credit.