Are the two hadiths that narrate the story of Ibn ʿUmar divorcing his wife sound, and how can they be reconciled, given that one mentions ʿUmar went to the Prophet and the other mentions Ibn ʿUmar went to the Prophet, in addition to a difference in the way the Prophet gave the command to divorce?

No contradiction exists between the narrations of the hadith concerning the Prophet's (peace be upon him) command to Ibn Umar to divorce his wife. The different narrations, which sometimes state that Ibn Umar himself informed the Prophet and other times that Umar informed him, are due to the narrators' abridgement of the incident.

The detailed narrations (such as those by Ahmad in the Musnad) clarify that both Umar and his son addressed the Prophet (peace be upon him) regarding this matter, or that Umar went first and then the Prophet (peace be upon him) sent for Abdullah. Abridging a report is permissible among scholars if it does not affect the meaning.