Shaun Edwards, who wants to play in his 11th Wembley final despite a broken thumb, has been bracketed with Glen Air at scrum-half. He is due for another X-ray today, but Stains said that he might wait until Saturday before making a final decision.
If Edwards plays, Air will drop to the bench, displacing Ady Spencer, the former Cambridge University player, who has been named as one of the substitutes.
The unlucky player is Dominic Peters, who has been a regular in London's side this season, but misses out for Wembley.
London's Wembley opponents, Leeds, report no new injury problems after their victory at Huddersfield on Sunday. Marvin Golden, Andy Hay and Daryl Powell came through safely, while Richie Blackmore should be available as well after being rested because of his persistent groin injury.
Stains' predecessor, Tony Currie, has put his name forward for the vacant coaching job at Keighley, who terminated the contract of Lee Crooks last week.
The Bradford chairman, Chris Caisley, has poured cold water on the idea that Henry and Robbie Paul could be on their way back to their native Auckland in the near future.
The pair played so well in New Zealand's defeat by Australia last Friday that stories linking them with a return to the southern hemisphere were inevitable, but Henry is contracted until the end of next season and his younger brother for a year after that.
Meanwhile, Henry has been cleared of any damage after being taken off late in the Test in Sydney with a neck injury.
London Broncos (v Leeds Rhinos, Challenge Cup Final, Wembley, Saturday): Tollett; Smyth, Fleming, Timu, Offiah; Hammond, Edwards or Air; Retchless, Beazley, Salter, Millard, Simpson, Gill. Substitutes: Toshack, Callaway, Ryan, Air or Spencer.Reuse content