@hollygs Reading thru your post and all the comments I don't see anything about bone scans. Are you getting DXAs or Echolight scans to track what results you are getting with the different meds?
If you are getting scans and have one at beginning and end of Evenity and one at the beginning of Tymlos (I guess that's the same as the end of Evenity?) then you can get another scan now and know exactly how you are doing on Tymlos. There's no absolute magic about waiting a year (other than insurance and money) for a scan. I've twice paid for DXAs rather than waiting till the year was up, because I wanted the information right away to make decisions about what I'm doing with my osteo treatment.

Others have given you good info on your situation. I agree that there is currently no research to show what happens following Evenity with Tymlos.
I could not find any. My guess is that it would work. But that is nothing but a guess.
A few months ago when I was researching this I was interested in following that sequence myself. I gave it up because I just couldn't find any evidence to support that path. I thought it likely that it would work but I did not want to chose a sequence with no evidence supporting it.

I searched the various osteoporosis forums trying to find people who were following Evenity with Tymlos or Forteo. I found 3-4 people who were doing or about to do that on their doctors recommendation. No one had completed a year on the follow up med and none had a scan yet to see the results.
I found an interview where Dr Michael Lewiecki a noted osteo doctor, mentioned that he had had one patient do that with success. He gave no further relevant details on that one case.
So if you have a baseline DXA scans and you get another DXA you may be our first test case. I'm guessing and hoping you will be successful.