I finally managed by setting up every bulb right next to Homey. They wouldn’t connect to Homey for the first time or be reset anywhere else. I just put a lamp with an E27 and a lamp with an E14 socket next to Homey. After setting up a bulb next to Homey (setting it for the intended zone straight away) I moved it to the intended spot and it kept working.
I have two GU10 spots which are located in the kitchen where Homey is, so no problem there. For lamps that are controlled by the same wall switch I had to remove the lamps that were set up to be able to set up the other ones one by one. Only when all of them were set up I could add the lamps I previously set up and control them individually using Homey.
Right now I’m trying to figure out whether I can use the Tradfri RGB switches and motion sensors with Homey, but no luck yet.