Johnstone, 19, is a front-row forward from Mackay in Queensland, who came to Sydney in 2016 to play with the South Sydney under 18s SG Ball team.
He graduated to the Rabbitohs’ under 20s squad in 2017 and has gone on to play 24 NYC games in the red and green.
Johnstone has re-signed until the end of 2020.
Rodwell, 18, is a prop-forward from the south coast of NSW, who headed to Sydney after being recruited by Souths Juniors as a 16-year-old.
He played in the South Sydney Harold Matthews Cup under 16s team and captained the SG Ball Cup under 18s side before joining the under 20s squad in 2017 where he played ten games.
Rodwell has also re-signed until the end of 2020.
Ta’avale, 19, can play across various positions in the forward pack and despite an injury-interrupted 2017 season, he proved himself to be a valuable member of the under 20s squad’s forward pack across his 18 games this year.
A big body standing 192cm tall and weighing in at 105kg, Ta’avale has a strong running game and is equally adept in defence.
Ta’avale has re-signed with the Rabbitohs until the end of 2019.