We are planning to go live with latest RPi image, based on Jessie Lite and the latest Development build of cloud client 5.9.10. I did the tests on RPi 3B, 2B, 1B using WiFi connection and web camera (except for 1B, it has just 2 USB ports, I used one for Ultimaker 2 and another for WiFi dongle). I manually setup WiFi on every PRi, the setup is super easy on all RPis, check it here. I did at least 2 prints on every RPi.
Load on the CPU is very low. Check the results here.
We plan to release it soon!