Is the menu of the Shabbat meals affected when Shabbat is the day before the observance of Tisha B’Ab (as is the case this year)
It is clearly permissible to eat meat on the Shabbat before Tisha B’Ab, even if Tisha B’Ab begins on Mosa’eh Shabbat. In fact, the Magen Abraham (Rabbi Abraham Gombiner, Poland, 1637-1682) writes that it is considered sinful to abstain from meat on the Shabbat before Tisha B’Ab, and such a practice is a "Minag Ta’ut" – an erroneous custom. Even during Se’uda Shelishit, which is the final meal before the fast, one may eat meat and have a lavish meal. The Shulhan Aruch writes that one’s Se’uda Shelishit before Tisha B’Ab may be "like the meal of King Shelomo in his time." And Hacham Ben Sion Abba Shaul (Israel, 1923-1998) ruled that if one customarily eats Se’uda Shelishit with a large gathering of family or friends, he may do so for Se’uda Shelishit before Tisha B’Ab, as well.
The only restriction that applies is that eating and drinking must be completed before sundown. As long as one finishes eating and drinking by sunset, he may have a large, lavish meal with a large group of people.