If you're only going to use midi and couple it to a softsynth, then just play along with the takes.  That is assuming you have a keyboard, etc..  The audio generated from it will be fine.
 
 

You should use the method I posted above. I do it all the time.  I have a client that will record multiple tracks of a voice over for a info /promo videos and I have to send samples of different music beds.  The music beds will vary in tempo and if I can get the click track to match the music bed it becomes very easy to edit the music to match the picture.  I can move things by measures and beats instead of constantly finding edit points in the music clip.
 
So I like I said...I clip lock the audio clips into absolute position and then I change the tempo at will to match the music bed.  At times I will add a crazy time signature in just one measure to get beat 1 to line up (like 19/32). Since I do it so often it only takes me a couple of minutes to do this even if the music track is changing tempos (tempi). 
 
Send me the Cake file and in 5 minutes I'll have the click match the music for you.  If the music was recorded with out a click I'll spend another 5 minutes and approximate it for you.  Ill send you back the Cake file.
 
PM me if you'd like

Jimbo 88
I clip lock the audio clips into absolute position and then I change the tempo at will to match the music bed.

The advantage of Set Measure/Beat At Now is that it calculates and inserts the exact tempo(s) for you, instantly. No guessing, and the result is dead-on, not approximate.

brundlefly

Jimbo 88
I clip lock the audio clips into absolute position and then I change the tempo at will to match the music bed.

The advantage of Set Measure/Beat At Now is that it calculates and inserts the exact tempo(s) for you, instantly. No guessing, and the result is dead-on, not approximate.

 
Yes, exactly.  That is what I do most of the time.  There are multiple ways to do this, but if I know for sure that the tempo is say...87bpm... and it needs to start a couple of seconds into the file, I might use a off beat measure instead of having different tempos.  You have options and many different ways to skin a cat. 

Don't change the tempo.
 
You have melodyne, good. take a good rhythm track like a guitar and drag that track to the timeline.
Presto chango the tempo map now follows that rhythm track. Sync your midi to that.

bitman
Don't change the tempo.
 
You have melodyne, good. take a good rhythm track like a guitar and drag that track to the timeline.
Presto chango the tempo map now follows that rhythm track. Sync your midi to that.

Oh Yea!  There is that one too...but still have to lock the clips or drag all the clips to the front.
 
Good one Bitman!

Sorry, I mis-read the original post on my tiny phone screen and thought it said MIDI instead of audio. Sorry bout that. If your audio clips are just a single clip per track, then before changing the tempo, just grab the front edge of clip and slide (slip edit) it to Zero (not sliding the whole clip, just the slipping the front edge of the clip). After you've slipped the edge of the clip to Zero, right click it and Bounce to clip. Now you can change the tempo without the audio clip moving around on ya as if it Was recorded from Zero. If it's multiple clips in a track, just bounce them to clip with the first one slip edited to start at zero, then it will be one clip that starts at zero allowing for tempo change without moving the clip.

GregGraves
 
 You can do anything all over from scratch, and it is the rare situation that the redo is not better than the original. 

I wish I could believe that. but I cant. You see its not just rare, its indeed a fact that each take has its own personality and feeling.
Capturing lightning in a bottle isn't just a catch phrase. Ive spent years studying, trivializing the fundamentals of replication. Its not as simple as one would think.
Its not just BPM, its several bpm, drifting at different times. Its not just plucking strings but attack of those strings.
 
For most intended purposes, yes, one can replicate a track rather easily.
 
But the percentage of capturing the same feeling... of said track, that's not as easy as hitting the record button and trying to "Redo" the track.