Both players featured for the Hawks last season.
Duckworth, a winger, scored three tries in seven appearances for Hunslet in 2014. Backrower Briscoe also made seven appearances, nothing one try.
“I’m delighted to add James & Luke to our 2015 squad adding extra competition to our outside backs,” said Hunslet director of rugby Darren Williams.
“Both were popular additions in our play off campaign towards the end of 2014 and fitted in well with the rest of the squad.
“James is a powerful finisher who is great at getting out of yardage and Luke is deceptively strong and has added utility value.”