The two forwards were placed on the transfer list at the end of last season by previous Rovers boss Grant McCann but have been involved in Moore's first team set-up since his appointment last month.
After confirming the club are no longer actively seeking to move the pair on, Moore started Kiwomya in Tuesday night’s Carabao Cup clash with Grimsby Town.
And he says both Kiwomya and Longbottom have the opportunity to battle for starts.
“They’ve continued to work hard,” Moore told the Free Press.
“When I came in here I said the slate is wiped clean with everybody.
“They have to work hard and be part of the squad. They've had their opportunity to show what they're all about.
“And I’ve had a good reflection of both of them, in terms of who they are as players and how we can integrate them back in the squad.
“I made it quite clear with the squad that there is competition not only to get in but also to keep hold of your shirt.
“That is exactly what we want at Doncaster Rovers – players competing not only to get in the team but stay in the team by playing well and performing well for the football club and being proud to put the shirt on.
“Over the last couple of games and towards the back end of pre-season I've had no complaints with that because there's been a steady rise and progression.
“In order for that to continue you have to keep working.
"Alex and Will have worked extremely hard and I would imagine both are looking for an opportunity to get in and stamp their claim.”
Prior to Tuesday night, Kiwomya's last appearance for Rovers came in the Carabao Cup last August when he came off the bench in the second round defeat to Blackpool.
Longbottom - who has made 11 senior appearances for Rovers – last featured for the club in the Checkatrade Trophy last November.