you need to enable the airtunes component logging in system->system->debug so it logs airtunes printouts...
AppleTV4/iPhone/iPod/iPad: HowTo find debug logs and everything else which the devs like so much: click here
HowTo setup NFS for Kodi: NFS(wiki)
HowTo configure avahi (zeroconf): Avahi_Zeroconf(wiki)
READ THE IOS FAQ!: iOS FAQ(wiki)