Yes. SONOS has a ‘Group’ feature that allows the same source to play in any combination of ‘Rooms’.
Note that there is a slight time skew between TV sound and Grouped players. This is not usually an issue unless you are playing TV sound and one of the Grouped players is in the same physical space as ARC and the TV. Music play is always time aligned with all members of a Group.
Remember Youtube is stereo only, so playing music videos from your Tv will not result in very much of the sound playing form the rears.
The Play 1's have been succeeded by the One SL's.