1) In yeshivos they like to quote the aphorism from R' Chaim that a chisaron in hasbara indicates a chisaron in havana. If you can't explain something, it's a sign that you really don't understand it. (see this post from earlier this year ). In last week's parsha, Shimon and Levi disagreed with their father Yaakov about how to respond to what happened to Dinah. When Yaakov chastised his sons, י֮ עֲכַרְתֶּ֣ם אֹתִי֒ לְהַבְאִישֵׁ֙נִי֙ בְּיֹשֵׁ֣ב הָאָ֔רֶץ, they responded and justified their actions, וַיֹּאמְר֑וּ הַכְזוֹנָ֕הא יַעֲשֶׂ֖ה אֶת־אֲחוֹתֵֽנוּ׃. In contrast, the brothers never revealed to their father what they did to Yosef and why they acted such. They didn't even have the courage to directly tell Yaakov their concocted story, but rather וַֽיְשַׁלְּח֞וּ אֶת־כְּתֹ֣נֶת הַפַּסִּ֗ים וַיָּבִ֙יאוּ֙ אֶל־אֲבִיהֶ֔ם וַיֹּאמְר֖וּ זֹ֣את מָצָ֑אנוּ הַכֶּר־נָ֗אא הַכְּתֹ֧נֶת בִּנְךָ֛ הִ֖וא אִם־לֹֽא׃. According to Rashbam וַֽיְשַׁלְּח֞וּ means through a messenger על ידי בני אדם שלא יגידו מי השולחים, אלא שיאמרו:א זאת מצאנו so that they could hide their hand in the whole affair. Why hide behind the veil of secrecy? Why not explain to their father why they acted against Yosef? R' Shmuel Birnbaum explains that when it came to Shechem, Shimon and Levi understood crystal clear what they needed to do and why their actions were justified. Therefore, they were able to answer their father. When it came to dealing with Yosef, the fact that they could not find the words to justify their actions indicates that the rationale for what they were doing was not really clear in their own minds.
2) Yosef is taken by the Midyanim and sold into slavery in Egypt וַיַּֽעַבְרוּ֩ אֲנָשִׁ֨ים מִדְיָנִ֜ים סֹֽחֲרִ֗ים וַֽיִּמְשְׁכוּ֙ וַיַּֽעֲל֤וּ אֶת־יוֹסֵף֙ מִן־הַבּ֔וֹר וַיִּמְכְּר֧וּ אֶת־יוֹסֵ֛ף לַיִּשְׁמְעֵאלִ֖ים בְּעֶשְׂרִ֣ים כָּ֑סֶף וַיָּבִ֥יאוּ אֶת־יוֹסֵ֖ף מִצְרָֽיְמָה׃ (37:28). The brothers present their story to Yaakov, who refuses to be comforted, וַיָּקֻ֩מוּ֩ כׇל־בָּנָ֨יו וְכׇל־בְּנֹתָ֜יו לְנַחֲמ֗וֹ וַיְמָאֵן֙ לְהִתְנַחֵ֔ם וַיֹּ֕אמֶר כִּֽי־אֵרֵ֧ד אֶל־בְּנִ֛י אָבֵ֖ל שְׁאֹ֑לָה וַיֵּ֥בְךְּ אֹת֖וֹ אָבִֽי (37:35) The Torah then ends that chapter by repeating what happened to Yosef, וְהַ֨מְּדָנִ֔ים מָכְר֥וּ אֹת֖וֹ אֶל־מִצְרָ֑יִם לְפֽוֹטִיפַר֙ סְרִ֣יס פַּרְעֹ֔ה שַׂ֖ר הַטַּבָּחִֽים. We then have an entire chapter devoted to the episode of Yehuda and Tamar, and return in Ch 39 to the Yosef narrative, וְיוֹסֵ֖ף הוּרַ֣ד מִצְרָ֑יְמָה וַיִּקְנֵ֡הוּ פּוֹטִיפַר֩ סְרִ֨יס פַּרְעֹ֜ה שַׂ֤ר הַטַּבָּחִים֙ אִ֣ישׁ מִצְרִ֔י מִיַּד֙ הַיִּשְׁמְעֵאלִ֔ים אֲשֶׁ֥ר הוֹרִדֻ֖הוּ שָֽׁמָּה׃. Alshich asks: why do we need that final pasuk in ch 37 before the episode of Yehuda and Tamar to tell us again about the Midyanim selling Yosef off? It really belongs to the start of ch 39. Instead of that chapter starting וְיוֹסֵ֖ף הוּרַ֣ד מִצְרָ֑יְמָה, eliminate those words and start by saying הַ֨מְּדָנִ֔ים מָכְר֥וּ אֹת֖וֹ אֶל־מִצְרָ֑יִם upon which time he was bought by Potifar. It is more concise, and does away with what seems an extraneous pasuk at the end of ch 37.
The Tzror haMor answers that the final pasuk of ch 37 which tells us וְהַ֨מְּדָנִ֔ים מָכְר֥וּ אֹת֖וֹ אֶל־מִצְרָ֑יִם לְפֽוֹטִיפַר֙ סְרִ֣יס פַּרְעֹ֔ה שַׂ֖ר הַטַּבָּחִֽים is not just there to convey information about what happened to Yosef. It is actually connected to the description of Yaakov's grief and his refusal to cease crying for his son. Chazal tell us that even when the gates of tefilah are closed, the gates of tears remain open. Yosef might have ended up anywhere. He might have been taken across the sea to a distant land or been carted off to the far reaches of the world. Were that to happen, the chances of his being reunited with his family would be slim. Thanks to Yaakov's endless tears, Hashem arranged things so that Yosef did not wind up too far from home. Of course it would be years before he ultimately was able to see his father again, but the possibility of that happening was already in place and the wheels were in motion from the get-go.
3) Abarbanel comments ואמנם בהפלגת אבלות יעקב הוא מקום תימה רב. The baalei mussar like the Seforno here: יאמר כי ארד אל בני אבל שאלה – קבל עליו אבלות לכל ימיו, מפני שארעה התקלה על ידו ששלח את יוסף אל אחיו Yaakov refused to be comforted because he saw himself as being at fault because he was the one who send Yosef to check on his brothers. It was the guilt that weighed him down. No wonder he refused at first to send Binyamin down to Egypt. Even though Shimon was being held captive waiting the brothers return, Yaakov had no hand in Shimon's being held, but were he the one to send Binyamin off to harm, in his mind he would be just as much at fault as when he sent Yosef.
3) I just saw this Midrash Talpiyot (bottom of first column( quoted somewhere this week and what an interesting find it is. וַיַּרְא־שָׁ֧ם יְהוּדָ֛ה בַּת־אִ֥ישׁ כְּנַעֲנִ֖י וּשְׁמ֣וֹ שׁ֑וּעַ Rashi tries to explain away כְּנַעֲנִ֖י as meaning a merchant. The M.T. writes that Yeuhuda married the daughter of Eisav (!), whose name contains the same letters as שׁ֑וּעַ. How could a tzadik like Yehuda have childen like עֵ֚ר and אוֹנָ֔ן ? It must be that their mother's genes from Eisav rubbed off on them.