Further to your answer to the question about the day of the aufruf, I understood that the chatan (whether Ashkenazi or Sefardi) is a chiyuv for an aliyah on the Shabbat after the wedding but not on the Shabbat before the wedding. Is my understanding incorrect?

According to the Ashkenazi custom calling the chatan to the Torah on the Shabbat prior to the wedding is a "chiyuv", meaning that the aliya of the Chatan takes precedence to a Bar mitzvah boy or a Yahrtzeit. This applies also for the Shabbat after the wedding. As Rabbi Blass already wrote in his answer, when to make a Kiddush for the Chatan's honor is another issue. (ביאור הלכה סי' קלו, ד"ה בשבת ויו"ט, זר התורה פרק ח)) However according to the sefardi minhag, calling the Chatan to the Torah is the Shabbat after the wedding and it is more an issue of honoring the chatan rather than an issue of a "chiyuv." ( (ילקוט יוסף קצוש"ע אבן העזר פרק ד - חופה וקידושין עמוד קט