On-loan Stoke defenders Shotton and Dickinson and Hull midfielder Doyle have all played for their parent clubs earlier in the competition while Gray played for Charlton in the first round before his move to Barnsley in late August.
Otherwise, manager Mark Robins has a full-strength squad to choose from on Tuesday, with no new injury problems following Saturday's 3-2 home defeat to Bristol City.
Robins must decide whether to recall Brazilian midfielder Anderson De Silva and the rested Jon Macken to his starting line-up while fellow striker Daniel Bogdanovic was on the scoresheet on Saturday.
Barnsley won at Lincoln and Reading in rounds one and two respectively and beat Burnley 3-2 at Oakwell in the third round to book a fourth-round clash with Robins' former club.
