Q. Dear Rov Shlit”a, If someone is invited to an engagement party during the beginning of Sefira, before Rosh Chodesh Iyar and they arranged a most beautiful meal. Is it correct to assume that this people will start the prohibitive traditions only after Rosh Chodesh Iyar and begin dancing and singing?
A. As mentioned by Poskim (See Shulchan Aruch. Mishna Berura and other Poskim O.H. 493.).
Mishna Berura (ibid.) rules that although it is permitted to celebrate at the above time an engagement party, however one should avoid dancing then.
However other Poskim permit and when one can assume that the people are greatly celebrating as they arranged a most beautiful meal, this group likely will start the prohibitive traditions only after Rosh Chodesh Iyar begins
Rabbi A. Bartfeld as revised by, Horav Yaakov Hirschman, Horav Dovid Pam, Horav Aharon Miller, Horav Chanoch Ehrentreu and Horav Kalman Ochs Shlit'a