Sure - the hypervisor is the isolation vehicle - the same as firecracker. The only? reason I can see for wanting to deploy N unikernels to one AWS instance is

Sure - the hypervisor is the isolation vehicle - the same as firecracker. The only? reason I can see for wanting to deploy N unikernels to one AWS instance is if you want full control on the orchestration of things like multi-tenancy, however, it is very much possible and it is possible on GCloud as well. It should be noted that you are in the same boat as firecracker here. They both use virtualization.