Ashton also scored a memorable try in the Cup, crossing the whitewash against Castleford Tigers.
Scott, who has come through the Eagles’ youth system, made four appearances in 2014, and is now looking to establish himself as a regular first-teamer.
“Jack, Connor and Tom all have lots of potential, and we are happy they have decided to carry on their development with us,” said Sheffield coach Mark Aston.
“Jack did well for us last season, but still has plenty of improving to do. We’re confident he can be a really good player.
“Tom has got better and better each year he has been in our systems, and we’re sure he can kick on again in 2015 and help us to be successful. Connor also did a great job when called upon and I’m sure he will make it at this level.
“All those years ago when we set the club up, the focus was to bring through young, local talent and to have them progress through our scholarships and academy into the first team.
“That is still very much the case and re-signing these players is us proving that.
“We want to make sure we have a strong core of youngsters playing in the levels below the first-team, that when they are called upon will do a good job.”