1) I understand that a network streamer (a UPnP streamer - not necessarily DLNA certified) should show up as a zone in MC. Can someone explain if there are any settings required to make this happen.
No settings are required. Provided the streamer announces itself correctly over the network, it will show up as a Zone. However you need to enable DLNA Controller in MC.
2) Assuming it is shown as a zone, how synchronised is linking streamer zones compared to soundcards? I know a while ago it was suggested the JR Id was not as good in this regard but that was a while ago.
There is nothing in MC that can synchronise DLNA devices, it is a problem that is inherent in DLNA itself, not MC, as the server has to send out separate streams to each device. It may or may not work, there is no guarantee. I believe Microsoft are working on something to allow synchronised Play To devices, maybe this has something to do with multicast messages.
3) If shown as a zone, can streaming music services be sent to the streamer, and is Spotify supported (I have not checked)?
Not as yet, there is a request I have seen recently on these forums for this to be allowed. I guess it means allowing the Connected Media items to be added as an item in the DLNA views.
Finally, with regard to UPnP does anyone know if the following scenario would cause problems?
1) You have MC acting as a Server as above and ripping music to a UPnP enabled NAS drive. A streamer looks to MC as a UPnP server.
2) You have the UPnP enable NAS also being looked to by the streamer so that music can be played back without the computer being on.
My concern is that the streamer is looking at two locations for the same content.
I do not believe that this would cause trouble but I'll let other people answer this one!
In any event, the fact that the streamer is looking at two locations for the same content isn't the issue, it's whether both MC and the NAS's own media server can read the same file at the same time. Certainly, if different files are being played then I can't imagine there being a problem, and if the MC computer is off then there definitely won't be a problem.
The two servers will appear as separate servers on the streamer, it's not as though the streamer will get confused as to which one it is streaming from.
However, if you are using MC as a server, there must be reasons why this is preferable over the NAS's internal server. So why would you then want to use the NAS's server? Are you (or your customer) willing to live with some limitations sometimes for the convenience of not having the MC computer on?