I wouldn't say nailed on, Glastonbury usually tries to go for acts in the first year of their album release so unless she has a random new 2025 album I would say it's 50/50.
In the case though, my prediction would be Olivia, The Boss and Fender. Not an ideal set of headliners for me but I guess they don't book it for me haha.
I really wanted to go to see Vampire Weekend, Pulp and Justice but I couldn't go this year. Thankfully, I watched most of the streams. Most of them are on youtube too if you missed them. I think Vampire Weekend had a better setlist than their Coachella performance. They didn't do the jam and playing cornhole on the stage thing which eliminates 2-3 songs. I really liked Pulp's rebroadcast on Friday night as well. I couldn't find Justice's stream yet.