Johnston was the star man in Halifax’s 48-6 victory over Doncaster, while Watson produced an assured performance in the Hawks’ 60-4 triumph against London Skolars.
Every week each coach in both Kingstone Press Championship competitions is contacted to help put the awards together.
Halifax half-back Ben Johnston continued his eye-catching start to the campaign with an influential display in his side’s 48-6 win over Doncaster.
Halifax coach Karl Harrison said: “Ben has had a great start to the season.
“He’s a young kid that we’ve given a chance to, and he’s grabbed the opportunity with both hands.
“He’s very similar to Rob Burrow in many ways – he runs at big guys and scares people to death because of this pace. They can’t get a shot at him.
“He’s still miles from the finished article, but his kicking game is improving and he will only get better when the fields dry up because he is extremely quick.”
Eaton said: “Jimmy was really good against Oxford last week, and he was great again when we played London.
“His push support has been good, he’s not making any errors and he’s slotted in defensively straight away.
“He’s not normally a centre, but he’s been doing a great job over the last couple of weeks.”