Am I right in thinking that a loaded template is just a "Starting point"... based off another FSM. If I change it, its not linked to the original right?
Correct. A template is separate from the FSM you used to create it. Also if you copy/paste a template, the pasted states are independent of the template.
But you can also reference the template directly in the PlayMakerFSM inspector, or using the Run FSM action. In those cases, changes to the template ARE applied wherever it's referenced.
And is there a clever way of getting a template from another project?
You can export templates in a unitypackage and import them into the new project.
NOTE: If the template uses globals you will need to export/import the PlayMakerGlobals asset as well!