Curious what your reasoning was for picking those calibers as choices. I could see limiting yourself to those if you were building an AR, but with a switch barrel 700 rig, the world is our playground. If you don't care to entertain that question, and just want us to stick to the choices you stated, I would go with the 6.5 Grendel. I've got all kinds of feedback to share if you would be willing to look at any other calibers.
Reasoning behind those calibers was really only for very low recoil options. Daughter is 3. Want to be sure she has the best experience possible without getting a scare from too much recoil. I'll add larger calibers and barrels as she grows.
I'd appreciate and be happy to look at any info you're willing to share.
Thanks