1) You can connect Converter client to Converter server either remotely (i.e. client is installed on another machine) or locally. If you use it locally then yes, it is where Converter standalone is installed.
2) I don't quite understand the question. Perhaps 1) answers this, too.
3) Yes, or it can be a powered on virtual machine regarded as physical by Converter.
4) Yes (if you happen to still use ESX 4.x, it might be classic ESX, w/o 'i')
5) Port 443 needs to be open on the vCenter server machine.
HTH
Plamen