Are management clusters and NFS required for vCloud 5.1 installs?

Just starting my vCloud journey and trying to make sense of requirements.

Can I install vCloud 5.1.1 on my existing vCenter environment without creating a seperate cluster/vCenter?  If so,  what are the possible concerns with this setup?   Does vCloud take all resources on the host that it manages or could I have Resource Pools outside of vCloud that woudl run non-cloud controlled VMs?

Is NFS required for 5.1.1?   If so,  is this an NFS share created on the vCloud Director server or an external NFS share?  If external,  what do admins do if no existing NFS infrastructure exists?

Thanks,

-MattG