I dont use Netbackup but my VCB server is running Data protector and esxreplicator. I dont see any reasons why you shouldnt/couldnt have both on a single machine as long as it is powerful enough to handle the jobs you plan to run. As far as i see the only requirement for VCB is to be SAN attached.
Well If you have a Powerfull machine there is no reason why you shouldnot use the same for both.
VMWare does not recomend to use VC and VCB on same host as Virtual Mount Manager used in VCB will have conflicts with Mount manager running in VC
Workstation and Converter also are not to be used on the same Machine..
Most of the installations I have configured use the prosy server as a media server. However, I have installed VCB on a Master/Media server without issue. Just follow the readme.html file that comes with the enabler as well as the installation guide. And make sure you use the latest comaptable version for your version of ESX.