Accepting Shabbos Earlier Than Family
I daven in a shul that takes in Shabbos early during the summer months. We don’t make an early Shabbos for the purpose of tosefes Shabbos, but rather we find it convenient. Does my wife have to accept when I do? I heard that Rav Moshe Feinstein said that’s only the case when it’s done l’shem tosefes Shabbos, not for convenience.
Secondly, I occasionally go to my aunt’s house for Shabbos and there’s only one shul where she lives and they take in Shabbos early. Do I have to accept Shabbos early if they are taking it in early solely for convenience?
The majority of Poskim reject this distinction and generally do not take into account the purpose of accepting Shabbos.
Therefore, to answer your questions:
1. Many Poskim hold that if a husband accepts Shabbos early, his wife and children must do so as well. Some hold that a wife and children may accept Shabbos whenever they wish, regardless of when the husband or father began the Shabbos. Even according to the lenient opinion, many poskim maintain that the wife (or children) may not perform any melacha specifically for her husband (or their father) during this time.
Regardless, If there is only one shul or if the majority of the community has accepted Shabbos, they must accept Shabbos as well.
See in the comprehensive guide for accepting Shabbos early chapter 3 and in footnotes 35 and 38.