Once I looked at my final scene (landmark) backgrounds, I thought they might not fit with the rest of the animation so well. With this in mind, I decided to take the collage background from the previous scenes and apply it to the images. This meant they would tie in better and the whole thing would be more consistent, rather than having a chunk of stop motion and a chunk of keyframed animation.
These are the final products:
My favourite out of the three is the Opera House, I'm really pleased with the way it's turned out, and think it will look great with the balloon over the top.