-What kind of power supply do you recommend? 850w is ok?
PSU better get more 850 W. you can choose 1000W or 1200 W or split 2x750 W.
-Motherboard and cpu: A normal Celeron would be ok, right?. Wich one exactly? I obviously also need to find a motherboard that supports that type of cpu. ASRock maybe is a good choice. Wich model should I choose?
if you want, can choose Asrock pro btc. has 6xGpu slot.