Mary comes to Erinsborough for her adopted daughter Paige's 21st birthday. She also meets Paige's biological parents Lauren (Kate Kendall) and Brad (Kip Gamblin). Mary apologises to Paige for turning up unannounced and reveals that her son Ethan (Matt Little) has been keeping her up to date with Paige's Business. Terese Willis (Rebekah Elmaloglou) later visits Mary and learns that she wants Paige to come to Singapore with her. During a meeting, Paige tells Mary that she once overheard her say the minute she arrived was the minute everything went wrong. Mary does not deny saying it, but explains that she had learned that Paige had been stolen and that her husband had lied to her, which eventually ruined their marriage. Lauren asks Mary to stay longer to show Paige that she cares. Terese encourages Mary to use Lassiter's Hotel for a Business event. Mary asks that Naomi Canning (Morgana O'Reilly) is not involved due to her prior connection with a client. Mary and Paige bond over a crafting event at Off Air, and Paige accepts Mary's invitation to Singapore. She later changes her mind due to her involvement in a police investigation. Before she leaves, Mary tells Paige that she is proud of her. She also mentions that Terese seemed pretty keen for Paige to go to Singapore.

An Inside Soap columnist thought Nick's fake-cancer plot was "dastardly" and added, "we didn't think there were many people around who are more wicked than Paul Robinson – but it seems he's well and truly met his match in Doctor Nick." Louise Rugendyke of The Sydney Morning Herald observed that Nick "seems to be as competent as Dr. Nick on The Simpsons". Daniel Kilkelly of Digital Spy branded Nick "one of the show's most twisted villains". Fotiou reprised his role in 2017 when Nick was reintroduced for Terese's breast cancer storyline. He returned on 31 July.

Cecilia Saint, played by Candice Alley, made her first screen appearance on 11 November 2015. The character and Alley's casting was announced on the same day. Alley auditioned for the role and learned she had been successful a couple of days later. She commented that the cast and crew had been very welcoming towards her. Of joining the show, the singer said "With such a love for acting, I feel so fortunate to be part of such an iconic Australian series and working with such an amazing team of people." Alley filmed her first scenes in August, and returned to the set in 2016 to continue her character's storyline. Cecilia was billed as "a mysterious woman" who becomes involved in a scheme to unhinge Stephanie Scully (Carla Bonner). Alley told a New Idea reporter that she enjoyed "being able to delve into a character who's also a single mother."

Mary is Paige Smith's (Olympia Valance) adoptive mother. Valance believed Liano was the ideal person to play Mary, commenting "She's exactly what I imagine Paige's mum would be." Liano's look and style was not changed for the part and she said that it was one of the reasons she was chosen to play Mary. Mary returned in February 2016.