Which side gets to choose the Misader Kiddushin, the side of the Chasan or the side of the Kallah?
The job of being Misader Kiddushin is customarily designated to the Rav of the city, and has become mandated in Halacha, with a prohibition against another individual taking the rights for Siddur Kiddushin without prior permission from the Rav. Hence, in previous times where each city and town had its own single Rav and Mara Diasra, that Rav would be the designated appointee to perform the Siddur Kiddushin of the weddings that take place in his city, and thus the question of which side gets to choose the Misader Kiddushin was not as common. Traditionally, the wedding would take place in the hometown of the Kallah, and hence consequently, the Rav of the hometown of the Kallah where the wedding is taking place would be the Misader Kiddushin. However, today in which there are many wedding halls available in areas that do not contain an appointed Rav who has jurisdiction over the area, or there are many Rabbanim in the same city who hold the equal rights for Siddur Kiddushin, the question is raised as to which side gets to choose this honoree position. This question has become even further common today when many Rabbanim of cities and communities give permission for others to be Misader Kiddushin in their place, upon the request of the families, and hence the question once again becomes raised as to who does the right of choosing the Misader Kiddushin belong to.
The law: It is a Mitzvah upon the man to marry the woman, and it is he who must give the ring, or other item of value, to the wife. Likewise, some Poskim rule that the blessings which are said under the Chuppah by the Misader Kiddushin are in truth the obligation of the Chasan to recite and the Misader Kiddushin simply acts as his emissary to do so for him. Accordingly, many Poskim conclude that the rights for choosing a Misader Kiddushin in a case that there is no Rav of the area to whom it must be delegated towards, belongs to the Chasan, and hence in a case where the two sides cannot come to agreement as to whom they desire to be Misader Kiddushin, the will of the Chasan and his family override. Other Poskim, however, note the old-age custom to traditionally honor the Rav of the wife’s community to be Misader Kiddushin and hence the rights belong to the Kallah and her side of the family. Practically, both sides are to get together and discuss the reasons and importance for their specific choice of Misader Kiddushin and see if they can come to an agreeable compromise. Otherwise, the side of the Chasan prevails unless there is an accepted custom in their community of affiliation to delegate these rights to the Kallah’s side. [see next regarding Chabad custom] Nonetheless, all the above is under the stipulation that both candidates for the position of Misader Kiddushin from the sides are Halachically qualified to be Misader Kiddushin, otherwise they should not be Misader Kiddushin irrelevant of which side is asking for them to do so.
The Rebbe’s opinion and Chabad custom: As per various documented oral testimonies of the Rebbe, the Rebbe stated that the choosing of a Misader Kiddushin belongs to the side of the Kallah. In some instances when the Rebbe was asked by the Chasan to be Misader Kiddushin, he replied that this matter belongs to the side of the Kallah and that they need to ask. Likewise, in a reply to an individual who seemingly was contemplating not attending a family wedding due to them not choosing a Misader Kiddushin of the Chasan’s choice, the Rebbe replied that the matter belongs to the side of the Kallah and he should not get involved. Thus, it seems clear that the Rebbe held onto the long standing European/Ashkenazi tradition to delegate the choosing of the Misader Kiddushin to the side of the Kallah. Nonetheless, amongst Chabad Rabbanim there are different views on this matter, with some stating to follow the side of the Kallah and others stating to follow the side of the Chasan. Likewise, in various Chabad publications of wedding customs, no mention of the Rebbe’s opinion is recorded, and some even write that the matter is inconclusive. However, with the above relatively new revelations of the Rebbe’s opinion, seemingly many in Chabad will adapt to the custom of following the side of the Kallah as the custom of our community in regards to Lubavitch couples. Certainly, after the Chasan’s side is informed of the Rebbe’s opinion, they will be much less reluctant in allowing the Kallahs side to make the decision, Veshalom Al Yisrael.
The rights for choosing a Misader Kiddushin in a case that there is no Rav of the area to whom it must be delegated towards, belongs to the Chasan, unless there is an accepted custom in their community of affiliation to delegate these rights to the Kallah’s side. Seemingly, the custom amongst Chabad Chassdim should follow to delegate these rights to the Kallah’s side, as was the Rebbe’s directive on various occasions.
 See Nitei Gavriel 19:1; Minhag Yisrael Torah 4 Nissuin 121; Nissuin Kehilchasan 1:356
 Rama Y.D. 245:22 regarding a guest Rav not being able to be Misader Kiddushin ion place of the Rav of the city; Chasam Sofer Y.D. 230 that today no other person, including even another Rav living in that community, may be Misader Kiddushin without permission from the elected and appointed Mara Diasra; Shvus Yaakov 3:121, brought in Pischeiy Teshuvah 49:2 in Teshuvah of Kneses Yechezkal that in the times of Rabbeinu Tam, the French Rabbis decreed that the rights belong to the Rav of that community, and one who transgresses this is placed in Cherem; Noda Beyehuda Tinyana E.H. 83; Maharam Shick Y.D. 396; Betzel Hachochmah 2:72; Nitei Gavriel ibid
 See Betzel Hachochmah 2:72
 See Mahariy Shteif 132
 Michaber E.H. 34:1; Tur 34; Rambam Ishus 5:23; Noda Beyehuda E.H. 1, brought in Pischeiy Teshuvah 34 in name of Teshuvah of Rambam that if said by another person it is a Bracha Levatala.
Other opinions: Some Poskim rule that the blessings do not belong to the Chasan and may be said by another person. [Rama ibid; Rosh] Nonetheless, even so one can argue that this is simply due to the reason explained next, and hence even in their opinion the rights really belong to the Chasan. [Chelkas Yaakov 2:115; Betzel Hachochmah 2:72]
 It became accustomed to have the Misader Kiddushin recite the blessings in order not to embarrass a Chasan who is illiterate. [Beis Shmuel 34:2; Taz 34:1 in name of Rashal]
 Chelkas Yaakov 2:115; Divrei Yisrael E.H. 22; Betzel Hachochmah 2:72
 Mahariy Shteif 132 in name of Shulchan Haezer
 Conclusion of Nitei Gavriel ibid
 See Mahariy Shteif 132; Nitei Gavriel 19:1 footnote 2
 Meaning that the individual is an expert in the laws of Kiddushin [and some of Gittin-see Sichos Kodesh 5723:3; Shulchan Menachem 6:171; Chikrei Minhagim 2:197] and is able to Pasken in these Shaalos. Today there exist many courses which certify Rabbanim in this field of Halacha, and in Israel, one must be licensed by the Rabbanut to be allowed to be Misader Kiddushin, which entails having throughout knowledge of the laws.
 See Michaber E.H. 49:3; Shvus Yaakov 3:121, brought in Pischeiy Teshuvah 49:2; Betzel Hachochmah ibid; However, see Taz 49:1, and Beis Shmuel 49:4; Igros Kodesh 18:197
 Printed in Chasuna Teshuros, as well as Yimei Bereishis p. 405; Kefar Chabad Gilyon 794:83
 Yimei Bereishis ibid [Rabbi M”M Yunik corresponded with us a similar story when his father Rav Berel Yunik was a Chasan and asked the Rebbe to be Misader Kiddushin. Seemingly this is the same story as that printed in Yimei Bereishi which does not mention the name of the Chasan]; Kefar Chabad ibid; Testimony from wedding of Rav Sholom and Etta Devorah Morozov 1957; Rav Dovid and Chava Raskin 1954
 Anonymous Teshurah
 In one case scenario with a Chasan who advised with me on the issue due to an ongoing debate between the two sides, I called various elderly Chabad Rabbanim in Eretz Hakodesh, and the final stance on the subject was to follow the side of the Chasan. This was many years ago and I do not recall which Rabbanim said what, but simply that this was the final ruling accepted by the two sides from the Rabbanim I spoke with.
 See Koveitz Chasuna of Kurtz from Afula footnote 85