Stamile played Agent Pearce for ten episodes of the show last year. According to TV Line, she will reprise the role for at least four more episodes in season six.
Burns - currently playing Wynn Duffy on FX drama Justified - will reappear in a recurring capacity as Anson Fullerton, one of those responsible for burning Michael Westen (Jeffrey Donovan).
His return sees the character looking for "other devious resources to enact his plans", Entertainment Weekly reports.
Burns previously had parts in Breaking Bad and Surviving Suburbia.
Meanwhile, Kristanna Loken, who appeared in one episode of Burn Notice last year as Rebecca Lang, will also return for multiple episodes.
Loken is known for her role in Terminator 3: Rise of the Machines and playing Paige Sobel on The L Word.