@Doop enjoy your new venture. Let us know how it goes.
On your current issues though, I would say. I believe you may have a java error. I was having a similar problem as you were on my Ubuntu virtual machine. I used openhabian to do install java and magically everything worked. I am not sure what the install difference was and I want to work with this issue more so I can document and have it fixed.
I still believe though you may have a power supply issue on your pi. There were several people that had problems similar to your initial freeze problem and it was found that a power supply was the culprit. Keep in mind moving away from openHAB but keeping the same hardware just means a failure later. So I encourage you to tuck the potential power supply issue away for now and if strange behavior appears later then you can address it. If nothing ever comes of it, then consider me wrong and enjoy automating!