Aumua, 42, was the Seasiders' assistant coach during the first three years of the program, beginning in 1988-89. BYU-Hawaii dropped softball in 1993, citing financial reasons, but has since reintroduced the sport to comply with the move from NAIA to NCAA Division II status.
"We're pleased to have someone of Roy's knowledge who is from our community and familiar with our campus," said Seasider athletic director Ken Wagner.
Aumua is a Kahuku High School and BYUH graduate.
Also earning a berth in the Big Island qualifying Saturday was Eric Yabuta, who shot a 147. Russ McGarry is the first alternate.
Jay Kurisu and Vance Lynch, who both shot a 142, made it through the Maui qualifying Saturday at Waiehu along with Stephen Molina.
Both the women's and men's championships were decided by default when the opposing teams withdrew. Finishing second in women's play were Jan Resuello and Lia Young; the men's runners-up were Danny McInerny and Alika Williams.
Some 20 men's AA teams and 15 women's open teams competed.
The event will be held Saturday, 11 a.m.-8 p.m., and Sunday, 11 a.m.-5 p.m., at Schofield Barracks' Richardson Pool. Admission is free.