Chanukah oil use Yes versus candles due to the miracle happening with oil on Chanukah lasting 8 days
Pesach Seder 3 matzos needed halachically and not only for kohein Levi and Yisroel but for all the steps of the Pesach Seder to make it through while the rest of Pesach only 2 at a time for lechem Mishna are needed
Rest on the list I have no opinion on but everyone has their own minhag of what they grew up with their family holding like halachically. Esrog With pitum or without. Open or closed lulav etc…. And the many other examples you mentioned. Sefardim use Sefer Torah standing up while leining from it so do sefardim say selichos for the entire month of Elul including through Yom kippur.