Q. Can women, family or friends, invited to a yohrtzait siyum (see question above), take also part in the siyum and eat meat during the 9 days, even if they are not helping to set up?

A. Nitei Gavriel (Bein Hametzorim 1: 41: 2, Piskei Teshuvos 551: 38: n. 201, quoting R’ Sh. Z. Auerrbach zt’l) permit women related to the siyum, to partake in the fleishig seuda.
Horav Shlomo Miller’s Shlit’a opinion is similar.

Rabbi A. Bartfeld as revised by Horav Shlomo Miller Shlit’a