My editor emailed me first, with a few, mostly minor, changes to the text: we have been tweaking it continually between us, getting it just right (hopefully!). You always worry, in case an editor suggests something you hate, but these are all good ideas that make the text stronger. Creating a picture book is very much a 'team effort'; as an author, you have to be open to other people's take on your project and able to welcome editorial input. It really helps though, when you feel you're in tune with the other members of the team, which I certainly do on this book.
A couple of days later, my art director sent through her suggestions for changes to the illustrations, mostly minor, but there are a couple of spreads that need a major rework. This is normal - it's rare that a set of roughs goes through without some reworked spreads. Again, it's important for an illustrator to be able to let go of their original idea and embrace the new suggestions: it can feel frustrating if you've put a lot of time into something that has to go, but it does usually make the work stronger in the end.
The spreads in question are the two pictured. My art director felt that I needed to show the ballet school in the top image, to make it clear that this is where they are coming from (good point) and that we should probably lose the cat. She felt the final spread, which we looked at recently, lacks the necessary intimacy for the end of the story, where they are making up - also true. I'll show you the re-works when I've done them.