1stly your IAD-CDG flight doesnt qualify since it was a flight on a non EU Carrier to the EU from outside the EU

that leaves your return, since it seems to have been a crew issue, the only crew issue that I think UA would be responsible for is if the plane needed say 6 FAs and UA ordered only say 4 or 5 . But if a crew member gets sick and cant work or if the crew are illegal due lets say to their Inbound having been very delayed due to weather I dont see why a Carrier should be held liable

What will trigger $$$ a friend of mines daughter was FIMed from LH to LX then over to KL and in the end they messed up the res and after arriving @ AMS had to wait some 4+ hrs till they were able to confirm her on a flight to NY. they gave her 600 euro I believe or it might have been $600 worth of euro. From what I hear EU carriers do pay out the money when they are in the wrong.