Why seven names for Jethro?

Question

Jethro was called by 7 names in the Tanach. Rashi summarizes:

שֶׁבַע שֵׁמוֹת נִקְרְאוּ לוֹ: רְעוּאֵל, יֶתֶר, יִתְרוֹ, חוֹבָב, חֶבֶר, קֵינִי, פּוּטִיאֵל He was called by seven names: Reuel, Jether, Jethro, Chovav, Cheber, Keni and Putiel. [Rashi on Ex. 18:1]

The Sources elaborate:

1-He was called יֶתֶר Yeter (from יִתֵּר, “to add”) because he caused the addition of a Torah portion, Yitro (Ex. 18:1-20:23) and he was he was “abundant” (yiter) in good deeds.

2-Jethro, because when he converted to Judaism a letter (vav) was added to his name: יִתְרוֹ.

3-Chovav חוֹבָב, because he “loved” (חִבֵּב) God and the Torah [Mekhilta d'Rabbi Yishmael 18:1:2].

4-Reuel רְעוּאֵל: Torah says Reuel was Chovav’s father, but sometimes children call their grandfather “father”. [Sifrei Bamidbar 79, on Numbers 10:29]

5-Keni קֵינִי [in Judges 1:16], because he was “zealous”(kinei) for God and “acquired” (kanah) the Torah [Mekhilta Yitro 1].

6-Chever חֶבֶר [in Judges 4:11], because he was the “associate” of God.

7-Putiel פּוּטִיאֵל [in Ex. 6:25], because he had renounced idolatry (niftar). A different interpretation: “he fattened calves” (pittem) for idolatrous sacrifice. [Bava Batra 109b]

(1) However, Balak, Korach and Sarah have Torah portions named after them and their names were not changed. Also, (3), (5) and (6) are the same general idea. (2) and (7) are also the same idea.

Do the Sources discuss why there was a need for this proliferation of names, not emulated elsewhere?

Answer 1

There are several questions and premises packed into this one question, and I don't know if all can be answered in a single answer.

The overarching question appears to be what Chazal to specifically create this proliferation of names for Yisro, and not for others. Secondary to that is that some of the reasons seem weak, like adding a portion, while Sarah, Balak and Korach "added a portion" by getting a parasha named after them (thus perhaps suggesting that they were going out of their way to create additional names). Underlying all of this is a desire for Chazal to be systematic and act with purpose.

In terms of how unique such a proliferation of names were within the thought of Chazal, Midrash Rabba on Ki Tisa provides a list of such persons:

ראה קראתי בשם זה אחד משבעה בני אדם שנקראו להם שמות. יש שנקראו לו ארבעה, זה אליהו, בצלאל ו', ויהושע ו', ומשה ז', מרדכי ב', דניאל ה', חנניה מישאל ועזריה ד', אליהו ד'.

It proceeds to elaborate each of those. But we see that Moshe had seven names (Yalkut Shimoni lists ten), and Yehoshua and Betzalel has six names. While Yisro is not one of the names mentioned, in its elaboration, we see one possible reason for naming these tzadikim by multiple names:

בצלאל, מה שקרא לו אומתו שלו, והקב"ה קרא לו חמשה שמות של חבה על שם המשכן

That is, the five additional names of Betzalel were names of Chiba, endearment.

In terms of Yisro, your list is an aggregation of sources (Mechilta, Sifrei, Talmud), and presumes that Chazal were monolithic. However, it is possible that those who gave some of the alternate names did not give (or agree with) the other alternate names. It could, rather, be a case of localized interpretation by different Rabbinic figures, each grappling with a different aspect or difficulty of the text under discussion. And, as DoubleAA mentioned in a comment, the Law of Conservation of Biblical Personalities is a common feature of midrash.

In terms of adding a parasha in the Torah, this is not exactly the same as having a parsha named after you. In the language of Chazal, the weekly portion in Bavel by which one finished the Torah was called a sidra, not a parasha. A parasha is a section, as between the petucha and setuma gaps. Yisro successfully added such a section in the Torah by proposing new laws of a system of judges. Moshe ran the idea by Hashem, who gave his approval, and so there was now a new Divinely ordained section of laws. That is not the same as Sarah who died, and whose burial is discussed at the start of one of the sidrot, Korach who rebelled and had to be dealt with, Balak who hired Bilaam and had to be dealt with, all who had names at the beginning of the sidra. Nor is it the same as Pharaoh who enslaved the Jews and thus "added" all the sidrot where the Hebrews were enslaved.