Who was this Zimri? In Sanhedrin 82b, we read:
Rabbi Yochanan said: [Zimri] had five names: Zimri, the son of Salu, Shaul, the son of the Canaanitish woman, and Shelumiel, the son of Tzurishaddai.Why equate him with Shlumiel ben Tzurishaddai? For we read, for example, in parshat Bemidbar, in Bemidbar 2:12:
Zimri, because he became like an addled egg [betza hamuzeret]; the son of Salu, because he outweighed [hisli] the sins of his family; Shaul, because he lent himself [hish'il] to sin; the son of the Canaanitish woman, because he acted in a Canaanitish fashion, [i.e., depravedly]; whilst his real name was Shelumiel the son of Tzurishaddai.
|יב וְהַחוֹנִם עָלָיו, מַטֵּה שִׁמְעוֹן; וְנָשִׂיא לִבְנֵי שִׁמְעוֹן, שְׁלֻמִיאֵל בֶּן-צוּרִישַׁדָּי.||12 and those that pitch next unto him shall be the tribe of Simeon; the prince of the children of Simeon being Shelumiel the son of Zurishaddai,|
Further, in the closed-canon approach Chazal typically take, we cannot have Zimri mentioned just once, such that we do not see him elsewhere. And so, he is identified with someone we know from elsewhere in the canon, as one of the nesiim of the tribes. (Similarly, Shaul ben HaKenaanit is the last mentioned son of Shimon, in Shemot 6:15: