I'm not sure if they try this right away, and it might not work out well, but I wouldn't mind experimenting with this at some point:
Rielly-Lyubushkin
Muzzin-Brodie
Sandin-Holl/Liljegren
I don't think Liljegren on the 2nd pair would work right now. Maybe if he was paired with last years version of Muzzin, but Jake has certainly taken a little bit of a step back this year. Maybe pairing him with Brodie will help settle his game down instead of expecting Muzzin to carry his partner.
Lyubushkin on the top pair is definitely higher in the line-up than he'd ideally be but he has played the majority of this season alongside Chychrun and the season before that OEL so he has experience playing in the top-4. I think his lack of puck skills would mean he'd struggle alongside Muzzin just like Holl has this season, which is why I don't think he'd be a good fit there. But Rielly would obviously be able to make up for that on this pairing.
The goal here is mostly trying to get Muzzin back to playing at the standard we've been used to seeing him at since we acquired him, and I think putting him with Brodie might be the only way to do that at the moment. So the other pairings just fall into place after that.