The answer is yes and no.

The 2 Ones are bonded to the ARC as part of the Home Theatre set up.  You can listen to music in this set up and you can set the way the ones act in music mode in the surround settings.  They can be set as Ambient or to deliver full sound and also the volume level can be set for them.

If you want to JUST use the wo ones then you would have to unbond them from the ARC and set them up in a stereo pair as another room.  This takes time and you’d need to do trueplay tuning(if you use that) every time you make this change.

As an aside how are you connecting your Turntable?  Do you have a Play 5/Five or  port/amp?  You cannot connect the Turntable to your system without one of these products that have a line input.

I have a second generation Connect that is currently unused.  I was hoping to somehow make use of that. 

That can work. Depending on the turntable to may need a pre-amp

You then need to decide if listening to that on your current Home theatre set up works for you.  If you decide you just want tp listen using the two play 1s then you would have to break the HT bonded group each time, and i’m betting that would soon get tedious.

Or buy more speakers ;)