But a good singer can take tofu and make meat out of it. Lukas made the point that he didn't really care what song he got, because he felt he could work with anything. He's right... if you are on a higher rung of talent, and you also know the band's sensibility, the song doesn't matter nearly as much as it does if you are more limited in your talent.
A mediocre, or at least LIMITED singer might be able to sound passable with some songs and some styles. A really good one will be able to either cross styles, or in some cases do the exact opposite--take any song and "own it" in such a way that they convincingly and interestingly make it into THEIR style (presumably hard rock, since they are auditioning for a hard rock band).
Dilana, Lukas, to a lesser degree Patrice, they all seem to be able to do that second thing. Someone like Toby or Jill seems more like someone more suited to the first. Both are potentially winning strategies. It's the people who can do neither who are up a creek without a paddle--those either locked into a style without the capability to appropriate other songs into it, or those who try to roam between styles but who can't quite pull it off.