You have a couple of choices. To run a real library sever and sync the changes, or to have the files on the server and point the clients to those files. There are plus and minus to both ways.
By running the client with the Read Only flag set, you'll not be able to write anything to the files or side car files I think. I doubt that you'll be able to do imports from the client as well.
The library should at the very least be reset when you start MC again next time. Wiping out the new imports.
If you open the library in read mode, you'll be able to add the imported files to the library, but you'll end up writing data to other files as well. You COULD go this way, and go in the library management and remove the "write to files when possible" option on each library field. That might prevent some writing.
The third option is to run a real library server and client setup. You can choose if you wan to activate sync or not on each client, effectively stopping sync of data from clients. However, this method also limits importing, as this have to be done on the library server in most cases. You can get around this by for instance import to a directory on the servers file share, and have the MC server pick up those new files with auto import.
I like to use the Library server and several clients. This increases the usage scenarios in my case. It also decreases maintenance by having a single place to do the editing, and having all data synced between clients. The limitations in editing files on the clients and importing from the clients is a bit negative though.
