1) just client side, you'll find that there is no option for installing fonts on the server.
2) That depends on the plug in. Some need to be installed on the server, others on the client, I recommend researching/discussing each such plug in on the site of the developer who produced the plug in.
3) Both TemporaryPath and DesktopPath are get function parameters that refer to locations on the client's machine. Both could, however, refer to locations on the server machine as well if a script using them is run from a "server context". This can be done by using a server admin schedule to run a script or by using the Perform Script On Server script step.'
4) If the files are currently embedded in their container fields, changing the storage option on the field to external will cause FileMaker to copy the images to the specified storage location and then update the container field to reference the copy stored at the external storage location. Don't try inserting new files with the "store a reference" check box selected as this is a different method not intended for use in a container field with external storage.
Thanks, Phil. Regarding answer 4, I don't see the "store a reference" checkbox (I'm using 13 Advanced). Are you saying if I change the storage option, and don't change anything else, I should be fine with existing and future documents?
Store a Reference is an option that can be selected from the Open File Dialog used to select and insert a given file into a container field. This is not a storage options specified for the field, but part of the insertion method used to insert the file.
What you describe should work, but I'd try a small "test database" first.