Given Yungblud's last tour sold reasonably well in arenas, as did his festival at MK Bowl this year I can't see him taking second stage headliner at DL.
I can see him giving it a break, and trying to push for R&L headliner with a new album cycle in a year or two. Controversial opinion I'm sure.
I was very pleased the use of vapes was banned on the Accessible Viewing Platforms. I saw Radiohead through a sea of fog, despite a no smoking policy already in place. I personally don't see it as being any different to smoking and agree with your intolerance! 😂