Raspberry pi 3 both Gateway and Controller
is it possible to make my pi3 a gateway for the sensors and also run a controller, all in the same board?
Yes it is possible. I have the NRF24L01+ attached directly to a pi3, with the mysensors gateway and MyController working on the one device. I added a RTC as well and have a neat and compact solution that wasn't possibe even a few years ago!
UPDATE -> [2 nov 2017] I kept getting a lot of crashes with the nrf-on-pi set up and the guys at mycontroller thought this might be the issue. I have now removed the gateway from the pi and instead run it on a 3.3V 8MHz pro-mini linked to the pi by serial interface - So far so good, but early days of testing.......