No.

A Play:1 can only be used in a stereo pair with another Play:1. SL’s can be paired with Ones.

@106rallye is correct that it’s not officially supported, but there are unsupported ways to do it:

1. If you use iOS, then SonoSequencr can be used: https://apps.apple.com/gb/app/sonosequencr/id967043604
2. If you’re technically capable, there’s a Python utility that’s not too hard to use: https://github.com/erikmansson/pair-sonos

Thank you! 

Can I group (but not stereo pair) play:1 with one SL and hence use AirPlay 2 on both?

[Edited]

Yes, this works with a Play:1 and an SL grouped together. That’s simply supported behaviour. Send the AirPlay audio to the SL.

It also works as a stereo pair, but make sure you assign the SL as the left hand speaker (so it’s the coordinator of the stereo pair).

That’s great. Thank you!

I have a Beam, and a pair of SL One’s. Can i buy a pair of Play 1’s to use in stereo with my other sonus products in another room? I ask cause the Play 1’s have gotten cheaper then the SL One’s.

Yes, you can group all Sonos speakers. You just can’t stereo pair speakers with dissimilar names.

So two PLAY:1s would pair, as would two Sonos Ones. But you can’t stereo pair a PLAY:1 with a Sonos One. 

Yes you can. I have a similar setup with the Beam and One SL’s  in my Dining Room and a stereo pair of Play:1’s in the Kitchen. Each room can be played separately or grouped together in sync.

I have both Play:1 and One sl and swear I was able to pair them before, but since a while it isn’t possible anymore. Anyone else ever experienced this?

Perhaps you are thinking of ‘grouping’ the two speakers, rather than stereo pairing them? The latter has never been possible, unless you have used some kind of 3rd party software as mentioned here earlier in the thread.
 

I’m not too sure if pairing two different types of speaker with different acoustic properties is going to sound good either? I’ve not tried it, personally speaking, but surely it must affect the soundstage?
 

I’m also wondering if it might affect any existing Sonos warranty/support?