Qur’anic narratives aim at guidance and moral instruction. Interpreters may nevertheless seek every historical detail of a story, even when that detail is outside the point made by the verse.
The account of the cow of the Children of Israel includes details relevant to the Qur’an’s argument, but unverified additions about matters not mentioned are not necessary. Likewise, the name of the dog associated with the People of the Cave does not explain the passage’s main purpose.
Standard: do not turn an unestablished historical embellishment into a required condition for understanding a verse whose meaning is already clear.