I too have a similar set up and ask a similar question: I have an arc and sub with an amp configured as “surround” with two third party ceiling speakers. I would like to know if I can still play music directly to the amp speakers in this configuration as it appears I cannot. Once they amp is configured as surround for my living room that has the arc and sub in it, they do not play (the speakers connect to the amp that is) do not play music when streaming audio only sources. Am I correct in assuming that once they are configured for surround, that I will need a surround source that supports the “rear left and right channels” in order for them to make sound? 

Nope. You would need to 'Remove Surrounds' and redo Trueplay (if you do Trueplay).

Then reverse the procedure to go back to HT.

Sonos HT setups are designed to function as a semi-permanent unit.

so you mean if I want to stream to the ceiling speakers, remove them from the surround HT config and use them as their own “room” and add them back to HT when HT is desired again? 

I know it is easy to do, but this was my first set up so was not sure if there should be some other way. 

To @SouthSound . That is a completely different question and should be posted as a different thread.

Got it.

Thanks very much for the answer. 

Hi. No, I was answering the question asked by the OP, not your question.