Does the Play:1 (Gen 1) connect to Sonos Beam for dual speaker set up?
Yes, all sonos speakers can be grouped together.
If I purchased another Play: 1 (Gen 1) will the two Play:1 and Sonos beam group correctly and have sound from all speakers?
This would give you the option of adding the two Play:1’s as surround speakers or leaving them as a stereo pair in another room.
If I purchased the new One SL or One (Gen 2) are these compatible with the Beam and the Play 1(Gen 1)
Don’t get the Sonos One if you want to add to the Beam as surround speakers, as the mic will be disabled - best to save your money and go for the SL. Please see answer one. :)
Moderator edit: It’s worth mentioning here that a Sonos One (or an SL) cannot be paired with a Play:1, for surround sound or for stereo.
Thank you this is very helpful!