Could you save what you currently have set up in this Project Template as a Track Template?
Then, when you open one of the existing projects up, you could insert from that saved TRACK template, and bring in all of that other stuff that way?
Please note I do not know that the above would work - it just seems like it might. I have a whole bunch of audio tracks and a midi track and a bus created as a TRACK template. It even has an instance of Battery 3 with a custom kit pre-loaded, and all the audio tracks are contained in a track folder for drums, and all the audio tracks output to the drums bus.
My point being is that if I could get that complicated with my Drums track template, I don't see why you couldn't do the same thing with whatever it is you want to pull in with your track template.
Give it a shot and post back,
Bob Bone