"One point of note is I would avoid p2v'ing vcenter if possible. As long as the database is on another host do a fresh install and connect to it.. it will be much cleaner."
You beat me to it!!!!
Also, *IF* it's possible, get another old host just like the physical one your vCenter is on, and scrape up a few $$$ for a "Standard license" or a less expensive "Essentials Plus Kit" [http://store.vmware.com/store/vmware/Content/pbPage.vSphereComparePage] and use those 2 hosts in an HA cluster and put your vCenter server in there. 
That should ease their minds on their worries.