If you want all 4 speakers playing together the load on your amp will be to low and the amp will most likely shut down. That CXA80 has preamp outputs. You can run a power amp and hook up the ceiling speakers to that amp and there will be no problem using all the speakers together!
Something like this for the ceiling speakers would work!
https://www.parts-express.com/Dayton-Audio-APA150-150W-Power-Amplifier-300-812
Something like this for the ceiling speakers would work!
https://www.parts-express.com/Dayton-Audio-APA150-150W-Power-Amplifier-300-812