As revealed earlier today Dolores performed at “Billboard Holiday Party” in New York City yesterday. Singer Emily Afton just shared on Instagram 4 photos and 2 small videos of the evening in one single post (swipe to see all pics and vids). 2 of them concerning Dolores.
“Linger” – a bit out of key as you can see on video below – and “Zombie” were performed for sure as well as a possible 3rd song but we don’t know which one yet.

Brb jumping back in time to tell my 16-year old self what I did last night… We played the @billboard holiday party and I got to sing with Mark McGrath (Sugar Ray), Chris Baron (the Spin Doctors), Dolores O’Riordan (the f$*%ing CRANBERRIES), Matt Scannell (Vertical Horizon), and Sophie B. Hawkins. IT WAS SO COOL (just realized the sugar ray song is in there twice but I can’t delete it so YOLO)

“Linger” – December 14, 2017 – NYC

UPDATE: After Dolores’ passing, billboard.com published a short “In Memoriam” video with images recorded from the audience at their Billboard Holiday Party.