Apple Logic Pro /LogicExpress Discussion

1)  I used Mainstage last week at church, mostly pad sounds.  I took a 1/8" to 1/4" jack from the headphone output to a DI box - then to the PA.  There was some slight distortion, faint but present.  Wondering if anyone has experienced that?  We felt it was low enough that the audience wouldn't notice when the band was playing so left it alone.

2)  I use Logic Pro on a MacBook Pro, firewired into a MOTU Traveler.  2 1/4" jacks from out 1&2 from the Traveler to my monitors. Sometimes I need to hear things out of iTunes, and those play out of the small MacBook speakers.  Is there a way to make iTunes play thru the firewire, and therefore thru my monitors?

Thanks!
Mike