Hello,
 
I need to increase the tempo of a prerecorded project  by 10 bpm... project includes both midi(drums/keys) and analog audio tracks(guitar/bass)... I would like to avoid changing the "sound" of the analog audio to much... my efforts in the past have made some of the audio tracks playback unnatural.
Maybe a 10 bpm change is just to much, and anything I do will sound weird...?
Thanks!

Yes however it will require patience and possibly separating parts into without the whitespace(silent parts) if you need it to be perfect.
 
First thing I would do is, make sure the project is set to the correct tempo. Import corresponding tracks/ Create the clips and individuallly stretch the clips using an appropriate algorithm or with careful editing with the Audiosnap tool or transient editing mode.  If you can just hope the for the best and time stretch each track by 10bpm.
 
Also be aware Melodyne can help with things like that to avoid any unwanted pitch drift. Anything over 10% usaully gets a bit weird after stretching.
 

MIDI will follow tempo changes. If you change audio into groove clips, they will also follow, but might still require extra work.
 
*IF* you are already deep into a project, the easiest by far is to complete it and tempo change the pre-master (all tracks bounced to a single audio mix down). Then you can slip-stretch that track to play with the tempo (and change it again and again till you find the right one). Commiting to "X bpm" and finding that in error is much simpler to resolve when only working with one track.

https://youtu.be/4nHOmGPeVc8

For the MIDI part of the project, itd easy, just set the tempo to the tempo you want it the MIDI will follow it. For the audio, you just need to click the bottom right part of the clip and you can change the tempo by dragging your mouse left or right, lower or higher or higher or lower tempo. do that for every audio track and you'll have a new tempo for that song.

Thanks all for the good suggestions!
Salud...

stretching audio isn't as easy as it seems. Choosing the correct algorithm will be key in how your audio sounds once you offline render it. Try Melodyne.