Unfortunately you can't easily do Mac-to-Mac syncing of iTunes libraries in that manner. Your best options for networked iTunes access are:
- iTunes Library Sharing: put your library on the server, and you can get streaming access from your MBP. Downsides: no remote/offline access, you need to be on the same network as the server; all media/playlist management has to be done on the server.
- iTunes Home Sharing: same streaming access as above, but you can also copy files from the server to your MBP. Downsides: it's not syncing, you need to manually select and transfer the songs you want.
Store iTunes Library on a Network Share: change the iTunes folder location (Advanced section in the iTunes Preferences) to a shared network drive on the server (or any shared drive, doesn't have to be a Mac). This gets you local control of the library, just like any standard functions. Downsides: have to be on the local network to get access.
- With this option you could make a second library (option-click iTunes when you open it) on the local drive with a smaller collection of songs you want for off-network access, but again, you don't have any syncing abilities, you have to manually add what you want.
I don't know that much about iPhoto sharing, I think it's more limited, but you can always put the iPhoto Library on a network share, as in the third option above, with the same limitations. There's also iCloud's Photo Stream, which is fairly limited, but may work if you just want to get recent photos from point A to B.
I can answer the second part of your question. Since you just updated the MacBook's iTunes settings to point to the NAS, it's iTunes library file still resides on the MacBook. This is a .itl file in your ~/Music/iTunes folder.
iTunes relies on this database to tell it what's in the media folder. If you add stuff to the media folder without adding it through iTunes (i.e. just dropping files in Finder, or using another copy of iTunes on another machine) then that .itl database does not get updated.
So when you add files through iTunes on your Mac Pro, it updates the .itl database on your Mac Pro, but not your MacBook, so the MB can't see those files. If you add anything through iTunes on the MB, the Mac Pro database won't have it, since the copy of iTunes that connects to that database did not process the files.
I have a similar setup to what you're doing: iTunes media on an external drive connected to my iMac, and a MacBook which I use ONLY Home Sharing on.
You might get the idea to move one .itl file to the NAS and open it in iTunes on both machines, and this will work, but you can/should never have it open in both at the same time. That .itl file is really just an SQLite database, and they don't allow simultaneous access, so I've never even attempted this.
With respect to your first question, check ~/Music/iTunes and see if there are any old library (.itl) files. It's most likely that iTunes is opening an old copy or a backup of the database. If you duplicated the database or started a new one before moving your media, this might be the cause.
Start iTunes and make sure the media folder is set correctly or make some other change in iTunes. Now go to ~/Music/iTunes and look for the .itl file that has most recently been modified. Move all the others out of the folder.
Quit iTunes and restart it while holding the Option/Alt key. This will bring up a dialog that lets you select which database to use. Select the .itl file you left alone and it will continue using that as the default library.
Best Answer
For the Time Capsule directly? No
Sharing is done via iTunes running, irrelevant of where the files are stored. However you can look at something like Subsonic to share the music with multiple devices.
In both instances however this needs to run off another machine connected to the time capsule.