Unsure how to proceed with claims on this one...
2 adults flying with two small children (age 3 and 5)
Flew on a DL issued ticket with a SK leg from OSL-LHR. (2h15 planned connection time)
Crew shortage caused a delay of more than 1.5h total (flight delay certificate shows 15:18 Actual time of arrival vs 13:35 scheduled)
The delay then caused us to miss the connecting DL flight from LHR-SEA... when we made it to the gate the flight was already closed. Delta then rebooked us on a non-stop flight 3 days later as a courtesy since it was their ticket stock.

We went back to terminal 2 to get lodging provided by SAS, and they booked us up for only 2 nights - since they had provided us alternative routing on KLM via Amsterdam with a 1h10 connection 2 days later. We kept the non-stop with Delta and paid ourselves for the third night.

Question is, do we file the eu261 claim for delayed flight to London, or a claim for expenses due to missed connection, or both?