That's great news! I think Chloe's stomach will be fine. If she starts having problems, just back off the Wellness Core a bit and give it to her after she eats some of the Iams.
Sydney is doing very well so far. She's eating the original without hesitation now. The kibbles are a little bigger than her Evo small bites, but not too much bigger. I still have a lot of the Evo left, so I'm going to just keep mixing the two together. She seems to be okay with it.
Again, I'm thrilled that Chloe likes her new food. Let's hope it is a good switch for both our furries!