Striker De Vita joined the Bairns from Livingston in January after his previous loan spell with Partick Thistle was cut short that month.
He made nine appearances in all competitions including three starts but had yet to find the back of the net when the season came to a premature end in March.
Fellow front man McMillan is looking for a new club after being released by St Johnstone at the end of his contract.
The 31-year old Irishman made 22 Falkrik appearances and scored four goals in League 1 last season.
Dundee goalkeeper Ferrie did not make an appearance last season as he spent his time at the Falkirk Stadium as back-up to Cammy Bell and Robbie Mutch.
The trio follow last season's top scorer Declan McManus in returning to their parent clubs at the end of their loan deals.