Thanks guys, you're officially better people that any of the in laws!
They seemed to have forgotten while they were busy arguing when would be the best times for us to fly back to the EU that would be the most convenient to them. Which ended up with us paying more for the tickets and having less days in the EU, because those flights were gone by then.
(I'm sure the in laws have all posted on Facebook, which I haven't checked yet and also wouldn't be in line with how they sent me a message previous years but whatever. I had a great weekend with my cousin, her husband and kids in Santa Barbara, and got a message on my birthday that the youngest (3) was wondering when we would show up again to spent time with them.)