Randall and Johns will move from development deals into the top 30 for the Knights, while Johns extends his time at the club.
Crossland's extension only takes the form of a one-year deal, while Randall and Johns will remain in the Hunter until at least the end of 2023 on two-year deals.
Randall in particular has had to wait an extensive period for his time as a top 30 contracted player, with the 25-year-old impressing during his 12 appearances for the Knights over the past two years.
A excellent defensive player, Randall has served as excellent back up to Jayden Brailey at dummy half over the past 24 months.
Knights' head of recruitment Clint Zammit said it was evident Randall could handle NRL level.
“Randy is one of the fittest and hardest working players in the squad,” Zammit said.
“Through his hard work and dedication to training, he has improved the little parts in his game. When he came into the team at stages this year, it was clearly evident he can handle NRL level.
“He is popular amongst the group and will continue to build his game over the next couple of seasons and continue to grow his contribution to the team.”
Johns made his NRL debut in 2020 for the South Sydney Rabbitohs before transferring to the Knights, where he has played six games in 2021 on a development deal.
The son of Matthew Johns, Johns is a five-eighth and second-rower who will bring extra versatility to the Knights outfit, and Zammit said he could expect to feature a lot more in 2022.
“Jack is an intelligent player who can cover a variety of positions,” he said.
“He came to the club on a development contract this year and made the progression from NSW Cup to NRL quite early.
Crossland's progress may be one of the more intriguing to follow in the competition during 2022. With Mitchell Pearce requesting a release, it could open a battle on who will partner Jake Clifford in the halves.
There has also been talk he may turn himself into a Connor Watson-esque figure and fill a position off the bench, something Zammit didn't deny in a club statement confirming the extensions.
“Phoenix is a local kid who has worked hard on his game throughout the year and impressed coaching staff with his attitude, particularly whilst up in Queensland,” Zammit said.
“He adds depth to our halves whilst also covering numerous positions which makes him valuable to our squad.
“He has matured on and off the field which has helped improve his game and we are excited to see him after another pre-season.”