Nice project. Even though some items are in a language I do not understand, the sketch provided me with a better understanding of the MySensors work. Thank you for making the connection of what I know and what I was having trouble understanding.
@Kokosnoot good solution. I remember the discussion in the early days of MySensors. I've powered the radio's for most of my sensors from the 3.3v regulator on the arduino board and for me that works perfect. But for my latest designs I decided to add a separate ams regulator for my radio's like the guys suggested in the beginning. Because you basically want the on board regulator to power the mcu only.