case: I have some projects, made in Sonar, which I want to cooperate with another musician (playing bass).
He does not have a DAW of any kind, but a iPad and he might also have access to an Macbook. 

Would it be possible to use his ipad for this? 
Thinking of garageband or something like that. Arturia would probably be overkill for this matter.
Can Sonar export my project in a media format which is readable for Garageband?

If he gets a line6 "mobile in" or iRig, this might be sufficient? 

In Garageband: I suppose he could record his bass playing in track 2 (my project in track 1) and have bass amplifiers and so on for hos own "feeling". Then export his bass recording in Garageband as a wav file, without any effects?

Anyone have a clue if this will work? 
I should have gone over to apple to check there, but I won't be seen there...

export the project as a wave...leave the count in on it, tell him the BPM and send the file.

He should be able to load a wave into any DAW on any OS/platform. 

He can then return a wave to you. 

Should have mentioned - he's not a computer guy... So if the iPad idea will work that seems the easiest. 


If he have access to a POD xt and a Macbook, I suppose the sound quality might be better? 

To be totally honest, and just to chime in, I'm sure GH's process is so simple that you could just tell him and there wouldn't be too much confusion.