If I’m understanding correctly what you want to do: you want to adjust your tempo track to your audio file to line up bar&beats to audio, and you want your midi track follow the tempo changes of the tempo track so it play in sync with your audio at the end?
1 - have all your audio tracks in linear time base mode
2 - have all your midi in musical time base mode
3 - select the Time Warp in the tool box… you’ll then see that you have an alternate Time Warp tool that you can select
It’s called "Time Warp(musical events follow) Take that one…
4 - line up your tempo track to your audio; other tracks in linear mode will remain unchanged and the ones in musical mode will adjust to the changes
The usage of the time warp tool is explain in section " Using the Time Warp tool in the Project window " at page 915 of the manual. more info can be digged around those pages also.
I just queried support to know how to have the same behaviour in the tempo detection tool as it would greatly accelerate the process. but so far I’ve had disappointing results.