Tom Holroyd, who had not played since suffering a foot injury in a January pre-season game at Featherstone Rovers, started at prop in Rhinos reserves' 40-34 victory at the Jungle.
Joe Gibbons scored two tries for Rhinos and Hunslet loan players Kiedan Hartley, Aaron Jones-Bishop, Cameron Berry and Jack Mallinson - who kicked six goals - also crossed.
Mekhi Bridgeman-Reaney, was Rhinos' other try scorer.
Elliott Wallis and Junior Vasuitoga both touched down twice for Tigers and Josh Thornton and Jack Sadler also crossed.
Danny Richardson, making his return from a fractured neck suffered three months ago, booted five conversions.
Leeds, who won the trophy in 2019 and last year, will face Catalans Dragons in next month's Betfred Wheelchair Challenge Cup final next month.
Rhinos were the only team to finish with a 100 per cent winning record at Saturday's Challenge Cup festival at the Allam Arena, in Hull, which will also host the final on Saturday, June 25.
They won all six of their matches in the round robin stage, including an 8-0 victory against Catalans, before a 36-6 semi-final defeat of Halifax Panthers, when England star Nathan Collins scored two tries and six goals and Josh Butler also touched down twice.
Catalans, competing in the Challenge Cup for the first time in its current form, grew stronger as the day progressed.
After losing their opening match to Leeds, they strung together six consecutive wins culminating in a 34-6 semi-final demolition of Wigan Warriors.
Betfred Wheelchair Challenge Cup festival round robin results: Hull FC 6 Wigan Warriors 36, Warrington Wolves 0 Halifax Panthers 18, London Roosters 0 Leeds Rhinos 20, Halifax 36 Hull 6, Warrington 0 Wigan 30, Catalans Dragons 0 Leeds Rhinos 8, Halifax Panthers 2 Wigan Warriors 11, Hull 18 Warrington 4, Catalans 30 Roosters 4, Halifax 0 Catalans 42, Hull 0 Leeds 18, Warrington 4 Roosters 20, Catalans 30 Hull 0, Halifax 6 Leeds 24, Roosters 6 Wigan 10, Leeds 8 Wigan 6, Catalans 40 Warrington 0, Roosters 6 Halifax 10, Leeds 22 Warrington 0, Wigan 4 Catalans 20, Roosters 10 Hull 8
Semi Finals: Catalans Dragons 30 Wigan Warriors 6, Leeds Rhinos 36 Halifax Panthers 6