TheRiverCard

I am traveling with another person in Italy and our flight (BA605, PSA-LHR) departing tomorrow was cancelled with short (1 day) notice. It would be great if some of you can offer to confirm, or disagree on whether my thoughts toward the case that I am facing right now is correct:

Myself: My final destination is LHR and after a lengthy phone call, I have managed to rebook on the same flight departing one day later, on Tuesday. This makes it effectively a 24 hour delay. I am entitled to claim E250 based on the fact that it is a Category 1 flight and has delayed for more than 4 hours.

My partner: She is on a separate PNR and she also had her ticket rebooked on the same flight. Her return flight is in fact PSA-LHR-HKG (all on BA) with 4 hours of stopover. She is entitled to claim E600 as it is a Category 3 flight.

We are both EU citizens but she does not reside in the EU, would this be a problem?

In addition to above, we will also be able to claim expense covering food, hotel and transport to and from the hotel. (I have booked a stay in an ok-ish 3* hotel and have kept some screenshots to show that the price was reasonable)

While rebooking, We have tried to asked the agent the cause of the cancellation but she was not able to find an answer. Am I correct that this would be the only excuse that they may be able to use to stop us from making a claim under EC261? (As they may claim afterwards that the flight was cancelled under extraordinary circumstances)

Finally, although flying two days later, we will also go to PSA tomorrow to return our rented car and will have a chance to visit the counter at the airport. Is there anything that I should beware of, or ask?

Thank you!