Akdamut is said by most, however, It is not the Chabad custom to recite it. (the Lubavitcher Rebbe would say it quietly.)
The Aliyah containing the Aseret Hadibrot is given to a prominent person.
The Chabad custom is that all men, women, children, and even babies and newborns (health permitting), should attend Shul to hear the Aseret Hadibrot. The congregation stands during the reading of the Aseret Hadibrot, facing the Sefer Torah.
Maftir is usually given to a learned and prominent person, due to the special significance of the Haftorah. The congregants read along in an undertone, and some have the custom to stand up while reading it.
Some have the custom of reading Rut in Shul on Chag. Although it is not the Chabad custom because the link between Rut and Shavuot is observed by the fact that one reads the entire Sefer as part of Tikun Leil Shavuot.
Yizkor is recited before Musaf. Those who leave the Shul for Yizkor may recite “Av Harachamim” after Yizkor.
Yizkor may be recited at home without a Sefer Torah.
