Mercer set a program record for wins, while Rachel Nieto recorded her 50th victory for Long Beach State.
Megan and Nicole McNamara along with Logan Mend and Tomas Sorra will represent Volleyball Canada in China in June.
Diaz, a 5-5 sophomore from Roswell, Georgia, an AAU All-American and Academic All-American, is part of the class of 2019.
The No. 7 Flyers rebounded from 2-1 deficit to capture Senior Night victory over No. 10 Loyola.
A consistent and balanced hitting attack helped the Nittany Lions to the five-set home win.
The 2016 NCAA Champion, beach volleyball player and two-time state javelin champ will compete for the Cardinal track and field team.
Hill, a 2015 PrepVolleyball Breakthrough Player, averaged 4.5 digs per set in 2016.
Cowan averaged 5.7 digs per set en route to all-district defensive player of the year, all-conference and all-area honors in 2016.
Mexico, Chile, Puerto Rico earned spots at the U19 World Championships with 1-2-3 finish.