I think we are getting closer to what I want, but it already didn’t work at all.
-C 5 option was already set for squeezelite but not for shairport. I set it yet. There I recognized, that hw:1 was set for both sqeezelite and shairport. I changed it to hw:0 for both and now squeezelite is also able to start and with it iPhone finds the raspberry via airplay.
But now my first problem is present again. In Kodi the hifiberry card is choosen as audio device, but no sound in Kodi. Shairport and Squeezelite are stopped while Kodi is running. (incidentally: there is no option to run Shairport and Kodi simultanously?). The option „disable internal audio“ is still enabled.
Again thanks for your help!!!!