Making a server with multiple instances a member of two effectively independent clusters
I cannot see any reasons as to why you would have any issues. Just be sure to add a file share or disk witness to the cluster, as that will ensure there is no "weirdness" in the quorum. As long as you set the AG's up correctly, I cannot see any reasons not to use your suggested approach. 
The only negative i can think of, is that it will be an additional environment to manage and maintain, but you are already doing that having 2 instances on your primary. Will you be using the VM's for the Read-Only connections?