After a day of experimentation with openHAB I finally decided to first build a prototype system, rather than cutting real wires and putting the actors in between. This is what my prototype looks like:
I must say it was in fact a good idea to start this way. The actors did not work yesterday for whatever reason, but after giving them a day to relax now and restarting my rPI they now work just fine. No more messages droppped no nothing. Maybe I will eventually figure out what the problem was, who knows.
On a different note, I tried out HomeGenie today as an alternative to openHAB and will give it a try. It seems a bit more intuitive and easier to setup. I do wonder if it also matches the openHAB capabilities and versatility. More updates soon.