Watching tonight's (11/15) credits, I noticed that Maddie Rice, guitarist with the SNL band (and formerly of Stay Human/Jon Batiste's edition of Colbert's Late Show band) is credited as one of the musical directors. I don't know if this is her first episode in that capacity, but I'm pretty sure this is new as of season 51.
The other musical directors are Lenny Pickett (saxophone, lead on the closing theme), Leon Pendarvis (keyboards) and Eli Brueggemann (also keyboards, and no relation, as far as I know).
Best,
David