It is definitely easiest if you still happen to have the add-in installers.
If you do not, you could share your whole add-in folder Scripting Guide > Creating Applications > Create Add-Ins with the JMP Add-In Builder > Installing M... . You might have to share some extra files AND edit them but I dont' remember anymore which (I used this method when I moved my add-ins from one laptop to another with different username). They might have been the addinRegistry.xml files.
Or in my opinion better option (but takes more time) is to rebuild the add-ins. I think you could script this or you can use Add-In Manager addin and then pointing it to the add-in folder directly. It is able to pick most of the things to rebuild the add-in.
-Jarmo