I think they will understand that you booked for 3 people, and they will make sure you have the sofa bed. I checked my booking and it was a Superior room with terrace (so we were on the main level, which I really enjoyed because we could walk right out a little side door and were at security in 30 seconds) and it said 1 large double bed and one sofa bed on my confirmation (even though that room was just me and DH).
I didn’t have to email them, but I found this contact form:
https://help.disneylandparis.com/hc/en-us/requests/new?ticket_form_id=6125893816850
Not sure if they would respond?
We live in Texas, so we go to both WDW and DL a lot (more DL in the last 5 years, more WDW when my girls were younger). DLP is really fun, smaller than DL or WDW to me, and has more thrilling thrill rides than the US parks. Our DDs love thrill rides, so they loved all of the coasters! It was very clean, and we really loved the drone and fireworks show! The LLSP system (essentially) was not used by too many, so the lines were very short and returns were almost always immediate. The show that we saw (Lion King) was spectacular!! But my DH stopped to go the bathroom on the way to the show, and then they would not let him enter (the show hadn’t started yet). So be aware that they close the doors a few minutes before the show starts and they don’t reopen it!
I was warned here that the food wasn't great, and that was our experience as well. Nothing seemed terribly fresh, and many of the food kiosks never opened or closed very early. We were just there, so it was very late November, so not their busy season. We were surprised at the lack of diversity of food options, as well as the lack of special holiday food and bev as we get here in the US parks.
We also were warned that the shopping is not very diverse, and this was true. We did find some things, and the shops in the Village stayed open later than the parks (which closed quite early to us). The weather was not great when we were there (high in the low 40s and misting/raining), but that is pretty expected this time of year.
We really loved the Art of Marvel hotel, and the theming was really cute! The Skyline bar was a lot of fun, and we also walked around the hotel to look at the comic book art. We didn’t turn the room TV on until the very last day, but there were some really interesting interviews with different animators on one of the hotel’s channels.
Your weather should be much nicer in August, and Arendelle will be open, and you should have a great time! Read the sticky to find out more about DLP! Have a great trip!