Some Rumoured Names I've seen floating arond, take with a grain of salt but two or three of these turning out to being right sounds plausible:
Nora Foss Al-Jabri (2nd in Norway NF 2012 with "Somewhere Beautiful")
Tone Damli (2nd in Norway NF 2009 with "Butterflies", also competed in MelFest 2013 with "Hello, Goodbye")
Kyle Alessandro (Finalist in the Norway NF 2023 as part of Umami Tsunami with "Geronimo")
LLL (Norwegian girl band that works with Ben Adams from A1)
Age Sten (Lead singer of Wig Wam who represented Norway in 2005)
Tolou (Norwegian TikTok star)
Lavrans (Norwegian The Voice 2024 alumni and finalist)
Ellen (no idea who this

Probably someone from some talent show, I don't think it's the one who sang for Eurovision 1975 though)
Mathilde SPZ (Semi-Finalist in the NF last year with "Woman Show"

)
Didrik Solli-Tangen (Represented Norway in 2010)
Morland (Represented Norway in 2015 with Debrah Scarlett)