The ranking cut-off at the ASB Classic is 77, meaning only players within that mark can attain direct entry, while Brisbane's sits at 52.
Shenzhen, meanwhile, hands out twice as much prizemoney but its rankings cut-off is closer to 100.
And edging the Chinese event is especially pleasing to tournament director Karl Budge, considering its introduction last year was billed as a blow to Auckland's chances of luring top talent.
"That's pretty rewarding for Auckland," Budge said. "It shows how well we're viewed by the players and how much they think this is a great place to kick off the year.
"Having Caroline inside the top 10 and Venus back inside the top 20, I think it gives us real depth at that pointy end with some excitement all the way through."
In addition to those two drawcards - who, with world No14 Sara Errani, had already been announced - Barbora Zahlavova Strycova (25) and Svetlana Kuznetsova (27) round out the top five seeds. Last year's top seed Roberta Vinci, precocious American Sloane Stephens and former winner Yanina Wickmayer are other notable names, while Budge was also excited about Erakovic's direct entry.
"It's great she can get in on her own rank and she's shown what she can do when she starts to play aggressive tennis," he said. "It'll be great to see the home girl get out there and showcase her talents, because they're pretty considerable."
Erakovic's ranking left the tournament with a spare wildcard and Budge a busy man on the phone yesterday. Already in consideration are former French Open winner Francesca Schiavone and two-time Classic semifinalist Jamie Hampton, while there is merit in selecting another rising star to join Ana Konjuh, the 16-year-old Croat in the middle of a three-year contract in Auckland.
"Do you go after someone who's been there and done that, with a higher profile but possibly on the way out, or do you get someone like Ana and form a partnership?" Budge said.
"I think [Konjuh] is a multiple Grand Slam winner in the future, and that's as excited as I get about a player. So it's really the opportunity cost."