I mean. They never said an album. Surprise releasing a single is kinda the norm nowadays. Also the surprise is the return of the artist; not the actual release. The release still sounds to be traditionally done; whether its a single or an album. Also, Q1 doesn't mean today. It's between now and March. So I'd say:
Katy Perry
Sam Smith
P!nk
Nicki Minaj
Avril Lavigne
are the main options tbh. P!nk and Avril need to come thru asap. Katy is my 2nd fav but I can wait tbh; I'm not really sure how I'm going to feel about her music this era after hearing Rise & some of the other things last year.