In terms of best practices and possibly future issues, would there be any issue running RHEL7 base images on GKE in production?
GKE doesn’t support RHEL7.
GKE offers the following node image options for your cluster: Container-Optimized OS from Google, Ubuntu, Container-Optimized OS with containerd (cos_containerd), Ubuntu with containerd (ubuntu_containerd).
Any image family updates or addition will post on this page:
https://cloud.google.com/kubernetes-engine/docs/concepts/node-images