Both players stepped up their recovery from injury at Alfreton Town's Impact Arena Stadium with Bunn opening the scoring for the visitors in the 27th minute.
The forward fired a low shot into the bottom corner to break the deadlock for the visitors against the run of play as the hosts had a early penalty claim for handball waved away.
Olly Dyson then doubled the advantage in the 39th minute, hitting a shot on the turn in a packed penalty area to put Town in control before half-time.
The interval saw both Scannell and Regan Booty replaced by Fraser Horsfall and Denison Carvalho with Dyson having a glorious opportunity to extend Town's lead late on with spectacular free-kick.
The win keeps Town’s slim hopes of a top two finish in the Professional Development League and a play-off place alive, with two games of the regular season remaining.
Huddersfield Town's Team (4-2-3-1): Joel Coleman; Jamie Spencer, Danny Kane, Rarmani Edmonds-Green, Jordan Williams; Lewis O’Brien, Regan Booty (c) (Fraser Horsfall, 46’); Jack Boyle, Harry Bunn (Ronan Coughlan, 69’), Sean Scannell (Denilson Carvalho, 46’); Olly Dyson