As far as the symbol is concerned, you should be able to rescue the definition from the *-cache.lib from another project that uses this component. Use a ‘decent’ text editor to copy the section relating to your component into a new file. Don’t forget to add the leading and trailing sections.
EESchema-LIBRARY Version 2.4
Save it as a .lib file - name it something suitable and move it to a place where you keep your personal libraries. You can then go to the Symbol editor and ‘Import Library’ to import your new library. You can add then add your new library as a ‘Global’ library and access it from your new project. You may need to add the data sheet details and other info contained in the .dcm file either separately or copy similarly it if you have a rescue.dcm file available.