The Leeds boss was in serious mood ahead of his side's Championship clash with Cardiff City this weekend.
Hull City are the latest Premier League side to be linked with Alex Mowatt, for instance, with a £7 million bid mooted by the Daily Mirror.
Redfearn, however, has reiterated his stance on the matter, warning the Leeds trio that they can quite easily get 'lost' at a bigger club.
"They've got to look at the bigger picture. At the moment, they're the main feature of what's happening at this football club," he said.
"With the other seniors and overseas players, they've turned our season around. The message is just stick with it.
"What they don't want to do is go to a big club and get lost in the system because it can happen."
Meanwhile, the Leeds boss couldn't deny the impact of missing midfielder Cook recently, with the 18-year-old sidelined due to ankle problems.
The youngster has been one of the undeniable stars of the Elland Road outfit's season but his absence has coincided with two defeats in two for United.
And Redfearn says Cook's importance to the side has been emphasised by their fortunes without him.
He explained: "Lewis is a really important player for us. He's had an outstanding season. When you miss good players, you do realise how important they are to the team."
Leeds host Cardiff at 3pm on Saturday afternoon, with a potential victory sending the Yorkshire side above the Welsh club in the Championship table. Both sides are currently locked on 52 points, with Cardiff ahead on goal difference.