Sorry for my late response, had no time the last few days.
I tried some settings:
If I deactivate the option „disable internal audio“ under tab „raspberry settings“, the hifiberry card is located at hw:1, so I have to set hw:1 as option in the settings of squeezelite and shairplay to play music via Iphone.
If I enable the option „disable internal audio“, hifiberry is on hw:0, which then I have to set in the option.
In both ways, I only can get sound in kodi via hdmi.
If option „disable internal audio“ is not set, hifiberry isn‘t available in kodi.
If option „disable internal audio“ is set, I can choose hifiberry card in kodi, but no sound.
So actually there is only the problem with kodi…