Marshall came out of the blocks with a 13-11 win in the first set before Jameson took one back in convincing style 11-5.
However, the class of Marshall shone through as he took the final two sets 11-9 11-5 to win the title.
Vette-Blomquist was the best performing New Zealander in the tough under-15 boys' division. He flew through the competition before coming unstuck in the semifinals.
He then produced a top performance against number two seed Oscar Curtis to take third place with a 11-6 11-7 11-7 win.
In the under-15 girls' division, Natalie Sayes was a cut above in her run to the final where she met Jena Gregory.
Sayes was stretched by her fellow Kiwi but came home with the spoils, winning 11-8 11-7 11-4.
Zoe Dykzeul, seeded fourth for the competition, had a good win over fellow Kiwi Nadia Hubbard to reach the semifinals of the under-19 girls' division where she came across the top seed Alex Haydon from Australia.
Dykzeul took the fight to the pre-tournament favourite, making Haydon work hard for points.
Haydon eventually pulled away and grabbed a straight-sets victory (11-7, 11-5, 11-7) to book her place in the final.
Dykzeul meanwhile settled for fourth after losing the third and fourth playoff to fellow New Zealander Courtney Trail in a five-set thriller.
The pair traded the first four sets to pin it on a decider but it was Trail who came through and snared the title.
New Zealand returned with a significant medal haul from the 2018 Oceania Junior Championships at the PCYC Centre in Brisbane, claiming seven of the 10 titles up for grabs.
Meanwhile the Trans-Tasman Junior Test Series started yesterdaywith Vette-Blomquist playing in the under-15 boys' team for New Zealand.