Obviously, knowing little about your kid (but knowing a bit about these two schools), it feels like Tufts might be a wasted ED app. But if you have a good fallback, you could do Cornell for ED1 and Tufts ED2 if your kid wants to feel like they took their best shot.
The calculation here has to do with the rest of the list. If those include schools that strongly favor ED, she couldn’t be missing a good shot at one of those for a very remote shot at Tufts.
I sense you really want to let her have her best shot at those 2, so my recommendation would be to find a couple of schools that will be a surer thing so this doesn’t end up being an insane gamble but instead, a guaranteed decent outcome with a shot at a dream.