Applying templates to existing sessions...

I hope someone can suggest an alternative approach:

I am producing an album; with a session created for each song I have been recording guides to tempo tracks in preparation for later tracking drums referenced to the guide tracks.

My concern is that once I have the drum kit miced & signals routed within a session to then save as a template, when I try to load that template within my earlier created sessions will the guides and tempo tracks be compromised?

I want to avoid having to re-add tracks, re-route, re-apply plug-ins and re-mix for the same drum kit setup within each ready prepared song session.

Instead should I export the guides as OMF files and import them to new sessions created over my drum kit template?

Can I export & import tempo tracks?

A Template is, effectively, a Project in its own right, so you can’t “merge” it with an existing project… it is intended to be the “starting point” for further projects.
So you would be better off exporting the necessary from those individual Projects then importing them into the Template…
You can use the File Menu>Export>Selected Tracks for audio and MIDI tracks, and the separate sub-menu item “Tempo Track”.
Open your Template project, Import the Tempo Track, then Import Track Archive.

I suspected as much, didn’t realise Tempo Track could be exported/imported though,

thank you for your help,