How sound and meaningful are the hadith: "An infidel and his killer shall never be reunited in Hellfire," and the hadith: "Satan shall not approach a turbaned head"?

The Prophet's (PBUH) saying: "A disbeliever and his killer will never be together in the Fire" is an authentic hadith narrated by Muslim, Ahmad, and Abu Dawud. Its meaning, as stated by An-Nawawi, could be exclusive to someone who killed a disbeliever in jihad, so that it may expiate his sins. Or, it could mean that the punishment for the killer of a disbeliever is something other than Hellfire, such as confinement in the A'raf (a barrier between Paradise and Hell). Or, it could mean that his punishment in the Fire is in a place other than that of the disbelievers, so they do not meet in the same location.