International Opera Studio

Thalia Cook-Hansen comes from the United States. After vocal studies in the USA and Canada, she completed her master’s degree at the Dutch National Opera Academy. In addition, she attended masterclasses with, among others, Elliot Madore, Floris Visser, and Lynne Dawson. In Amsterdam, she appeared as Nerina in Haydn’s "La fedeltà premiata", Fanny in Rossini’s "La cambiale di matrimonio", Bastienne in Mozart’s "Bastien et Bastienne", and Adele in "Die Fledermaus". She also sang Barbarina ("Le nozze di Figaro") at the Estates Theatre in Prague, as well as the First Lady ("Die Zauberflöte") and Mademoiselle Silberklang ("Der Schauspieldirektor") in Toronto. Her repertoire further includes roles such as Bubikopf in Viktor Ullmann’s "Der Kaiser von Atlantis", Singer No. 1 in Conrad Susa’s "Transformations", Amore in Monteverdi’s "Il ritorno d’Ulisse in patria", and the title role in Donizetti’s "Lucia di Lammermoor". Since the 2025/26 season, she has been a member of the International Opera Studio at the Zurich Opera House.

Karima El Demerdasch is a German-Egyptian mezzo-soprano. She studied in Cairo and at the Guildhall School of Music and Drama in London with John Evans. In 2024, she was a finalist at the Kathleen Ferrier Awards and in 2023 participated in the Georg Solti Accademia. In Guildhall School productions, she performed roles such as Prince Orlofsky ("Die Fledermaus") and Dido ("Dido and Aeneas"). In a 2023 production by Opera Kipling, she sang the title role in "La Cenerentola" at the Upstairs at the Gatehouse theatre in London. In 2025, she took part in the Young Singers Project of the Salzburg Festival and made her debut at London’s Barbican Hall. Since the 2025/26 season, she has been a member of the International Opera Studio at the Zürich Opera House.

Evan Gray is a Swiss bass-baritone from Winterthur. He began his musical training as a treble in the Zurich Boys’ Choir and later transitioned to the bass vocal range. After his initial vocal studies at the Winterthur Conservatory, he went on to study at the renowned Curtis Institute in Philadelphia. His previous roles include the Forester ("Das schlaue Füchslein"), Figaro ("Le nozze di Figaro"), and Leporello ("Don Giovanni"). As an accomplished recital singer, he has performed Schubert’s "Winterreise" and Vaughan Williams’ "Songs of Travel" on multiple occasions and has worked with artists such as Julius Drake and Robert Holl. From 2023 to 2025, he was a guest at the Marlboro Music Festival, where he developed a close artistic relationship with pianist Mitsuko Uchida, who has invited him again for the 2026 summer edition. Since the 2025/26 season, Evan Gray has been a member of the International Opera Studio at the Zurich Opera House.

Guram Margvelashvili comes from Georgia. He completed his vocal studies in 2024 at the State Conservatory in Tbilisi. From 2019 to 2023, he was a member of the Tbilisi Opera Studio, where he performed roles such as the Priest and Papageno in "Die Zauberflöte", Valentin in Gounod’s "Faust", as well as the title roles in "Don Giovanni" and "Eugene Onegin". He also sang Belcore in Donizetti’s "L’elisir d’amore". Guram Margvelashvili has received several scholarships and was a finalist in the International Singing Competitions Giuseppe Di Stefano in Sicily and Tamar Iveri in Georgia. Since the 2025/26 season, he has been a member of the International Opera Studio at the Zurich Opera House.

Cashlin Oostindië is a Dutch mezzo-soprano. She received her training at the Amsterdam Conservatory and in Athens, as well as privately with Lauren Athey-Janka and Eva-Maria Westbroek. During her studies, she was a member of Young Opera Noord Holland, sang Marcellina ("Le nozze di Figaro"), participated in the chorus of Poulenc’s "Dialogues des Carmélites," and performed as a soloist at the Lefkas Music Week Festival in Greece. In concert, she has sung the alto parts in Bruckner’s "Requiem" and Rossini’s "Petite Messe solennelle." She regularly gives song recitals in the Netherlands with pianist Florence van der Does. Since the 2025/26 season, she has been a member of the International Opera Studio at the Zürich Opera House.

Italian soprano Mariam Suleiman completed her vocal studies at the Conservatorio di Musica Santa Cecilia in Rome under Virna Sforza. In 2023/24, she took part in the "Fabbrica" Young Artist Programme at the Teatro dell'Opera in Rome, during which she appeared in the title role of Pauline Viardot's "Cendrillon" and in concerts in Tokyo and at Expo 2025 in Osaka. In 2025, she won the competition Voci in Barcaccia. Largo ai giovani!, organised by the Italian broadcaster Rai Radio 3. She was also a finalist at the Teatr Wielki's International Stanisław Moniuszko Vocal Competition in Warsaw and at the Concorso Renata Tebaldi, where she received three special prizes. In 2025/26, she took part in the Mascarade Opera Emerging Artist Programme in Florence. Her most recent engagements include Isabella in Salieri's "La partenza inaspettata" at the Reate Festival 2025, the world premiere of Silvia Colasanti's "Sacred Goddess, Mother Earth" with the Filarmonica Arturo Toscanini in Parma, and the soprano part in Pergolesi's "Stabat Mater" with the Haydn Orchestra of Bolzano and Trento in Bolzano. At this year's Salzburg Festival, she appeared in "King Arthur Junior". Since this season, she has been a member of the International Opera Studio at the Zurich Opera House.

Natália Tuznik, soprano, was born in Budapest and completed her vocal studies at the Franz Liszt Academy of Music there. She was awarded the Junior Prima Prize. In 2023, she was a member of the Opera Academy at the Teatr Wielki in Warsaw and the following year took part in the "Exzellenz Labor Oper," founded by Hedwig Fassbender. She attended numerous masterclasses and worked with artists such as Éva Marton, Claudio Di Segni, Anatoli Goussev, Izabela Kłosińska, Fausto Nardi, Katelan Trần Terrell, Michał Biel, and René Massis. In 2022, she made her debut as Wellgunde ("Götterdämmerung") at the Hungarian State Opera and sang the First Lady ("The Magic Flute") on a tour of Japan. At the Hungarian State Opera, she has also performed the title role in Gluck’s "Iphigenie auf Tauris", Donna Anna ("Don Giovanni"), Alice Ford ("Falstaff"), and most recently Countess Almaviva ("Le nozze di Figaro"). Since the 2025/26 season, she has been a member of the International Opera Studio at the Zürich Opera House.

Salvador Villanueva is a Mexican tenor. He completed his vocal training at the Universidad de Sonora and subsequently at the Mexican Opera Studio, where he sang roles including Goro in "Madama Butterfly" and Remendado in "Carmen." In the 2023/24 and 2024/25 seasons, he was a member of the Opera Studio at the Amsterdam Opera, performing roles such as Gastone ("La traviata"), Borsa ("Rigoletto"), the tenor role in Tom Johnson’s The Four Note Opera, and the Sailor ("Dido and Aeneas"). In 2024, he returned to Mexico to sing the title role in Gounod’s Roméo et Juliette. Salvador Villanueva was a finalist in singing competitions in Mexico City and ’s-Hertogenbosch. He has been a member of the International Opera Studio at the Zürich Opera House since the 2025/26 season.

Ava Linvog is from Seattle. After studying at the Eastman School of Music and Vassar College, she worked as a freelance répétiteur based in New York City. In the USA, she has collaborated with Opera Omaha, North Carolina Opera, the St. Petersburg Opera Company, and the Brevard Music Center. Ava Linvog has given song recitals in New York, supported by City Lyric Opera, the Gerda Lissner Foundation, and Glyndebourne America. In 2025, she was a Vocal Piano Fellow at the Music Academy of the West and subsequently a scholarship recipient at Arizona Opera. Since the 2025/26 season, she has been a répétiteur and a member of the International Opera Studio at the Zürich Opera House.