I think people are both overestimating and underestimating Kilian:
Pros:
He is used to running 24 hours +
He is the greatest trail Ultra runner of all time (arguably)
He once trained for 5 days without eating till he passed out
If you had to chose somebody to break this record it would have to be Kilian or Jim or Zach. (I actually favor Jim with his more efficient form.)
Negative:
Lack of road experience - does that even matter?
Lack of experience running 24 hour around a track - This is the biggest red flag, every race you do like this you learn and adapt - it's an iterative process.
Nutrition - look at Zach's podcasts on how much thought he puts into nutrition and going ketogenic. You have to be a fat burning machine to do this. Kilian just wants to eat a few bars and gels.
Norway in winter?
Sub optimal preparation - i'm not sure what his mileage per week is leading up to this - look at zach bitter's build up to the 12 hour record.
Anyway despite any armchair criticism at least he is trying!
But no way he gets this on the first attempt IMHO
I get the feeling that this is being done to promote the new Salomon Phantasm, rather than a serious attempt at the record. Anyway he will learn from it.