Their children were born on the Gold Coast before the family moved to New Zealand 13 years ago. The pair pursued gymnastics careers before branching into their respective sports.
They will be performing in front of Australia-based family on their mum's side, including a selection of grandparents, cousins, aunts and uncles.
The siblings are avowed Kiwis, and the nurturing they have received on the North Shore is about to pay dividends at international level.
"It has been a long time waiting," Olivia says. "I was recently looking through my training diaries from when I was 13 [and still a gymnast]. I wrote that I wanted to represent New Zealand at a Commonwealth Games."
Olivia finished her final year at Kristin School in December. She will pursue her pole vaulting dream after shadowing 21-year-old Eliza McCartney through the age-group ranks.
McCartney has gone on to record a personal best of 4.82m and earn a bronze medal at the Rio Olympics.
McTaggart's top vault is 4.40m. Like McCartney, she is coached by Jeremy McColl, the guru who has transformed the discipline into a world-class operation in this country. They train out of the Millennium Institute.
"I was a gymnast, and so was Jeremy, which makes it easier as to how our bodies work and how the technique works within pole vault as a similar sport," Olivia says.
She made the transition as a 14-year-old after suffering back problems, but believes there are similarities.
"Pole vault has the same spatial and body awareness going upside down. You can't be scared. I've been a thrill-seeker all my life, going bungy jumping etcetera."
Cameron was lured to the barbell after the 2010 Commonwealth Games when he sought a change in sport. Mum Amanda had seen a story on weightlifter Richie Patterson returning from Delhi with a silver medal.
Patterson was soon Cameron's coach.
"It was hard to leave gymnastics because that was all I'd known since I was five.
"I was a teenager who'd been training 30 hours a week. I had way too much time on my hands. Mum suggested I give weightlifting a shot.
"I walked into a gym, threw a broomstick above my head and Richie said 'that's my athlete'. He's since become a confidante as well as a coach."
Patterson's already mentored Cameron to a few international competitions.
The pair also trained in Finland near Santa Claus' hometown of Rovaniemi in the Arctic Circle before Patterson competed in the 2014 Commonwealth Games.
Just days after winning a gold medal and getting married in Glasgow, Patterson travelled to oversee Cameron's youth Olympics debut in Nanjing.
"There was 24 hours of sunlight a day and we recovered from training in traditional Finnish saunas.
"Santa brought me a few personal bests while I was training there," Cameron quips.
Not to be outdone, Olivia's also received largesse from overseas competitions.
Last year, she earned a tin of sausages for finishing third in front of more than 2000 party goers in Jockgrim, Germany after striding down the laneway to AC/DC's Thunderstruck.
Cameron acknowledges weightlifting is a sport often beset by doping. That has influenced his career choice.
"I'm working semi-fulltime at a drug detection agency to ensure every work place is a safe environment.
"Anti-doping is a big thing in New Zealand and we have some of the best testing in the world. I'm proud to say I'm tested all the time and compete on the world stage as a clean athlete."
A key to the pair's success has been routine. Both have contrasting methods for achieving an equilibrium before and after competing.
"I have scrambled eggs before every competition, then slap my legs to get pumped up," Olivia says. "It's about finding the motivation to deal with any mind blocks. I take a moment to think how good the feeling of getting over the bar is.
"I smile to myself, like Eliza, and that helps me stay motivated."
"I recently came up with a one-word strategy to drive me on the platform," Cameron adds.
"Mine is 'process', and I follow that day-in day-out. It's not something that changes with the environment.
"I make sure I'm cool, calm and collected to go through certain movements, regardless of the weight on the barbell."
That does not always hold true once his event is over.
"Liv and I tend to show off on competition platforms. The crowd drives you to do your best. Some shy away from that, but Liv and I love that environment.
"When I get a new record, or go six lifts from six, I throw in a cheeky backflip."
"And I'll be there judging his technique," Olivia ripostes.
Regardless, the pair are set to somersault into the public eye this autumn.