Are Vincenzo Bellini and Nikolai Rimsky-Korsakov both composers?
yes
Vincenzo Bellini
Vincenzo Salvatore Carmelo Francesco Bellini (] ; 3 November 1801 – 23 September 1835) was an Italian opera composer, who was known for his long-flowing melodic lines for which he was named "the Swan of Catania".
Nikolai Rimsky-Korsakov
Nikolai Andreyevich Rimsky-Korsakov (18 March [O.S. 6 March] 1844 21 June [O.S. 8 June] 1908 ) was a Russian composer, and a member of the group of composers known as The Five.
 He was a master of orchestration.
 His best-known orchestral compositions—"Capriccio Espagnol", the "Russian Easter Festival Overture", and the symphonic suite "Scheherazade"—are staples of the classical music repertoire, along with suites and excerpts from some of his 15 operas.
 "Scheherazade" is an example of his frequent use of fairy tale and folk subjects.
Christmas Eve (opera)
Christmas Eve (Russian: Ночь перед Рождеством , "Noch' pered Rozhdestvom"), is an opera in four acts with music and libretto by Nikolai Rimsky-Korsakov.
 Composed between 1894 and 1895, Rimsky-Korsakov based his opera on a short story, "Christmas Eve", from Nikolai Gogol's "Evenings on a Farm Near Dikanka".
 The story had been used as the basis for an opera at least three times previously, including for Tchaikovsky's "Vakula the Smith" (1874).
 Oliver Knussen writes that "Rimsky is only interested in recreating the atmosphere of the folk-tale, fleshing it out for his stage pageant in a comparable way to Humperdinck in "Hansel". Andrey Rimsky-Korsakov
Andrey Nikolayevich Rimsky-Korsakov (Russian: Андре́й Никола́евич Ри́мский-Ко́рсаков, "André Nikolájevich Rímskij-Kórsakov", October 17, 1878 – May 23, 1940) was a Russian musicologist and son of the Russian composers Nikolai Rimsky-Korsakov and Nadezhda Rimskaya-Korsakova.
 He was encouraged in musical pursuits, playing cello in the family string quartet.
 However he did not pursue music as a career until late in his life. Pyotr Ilyich Tchaikovsky and the Belyayev circle
Pyotr Ilyich Tchaikovsky's relations with the group of composers known as the Belyayev circle, which lasted from 1887 until Tchaikovsky's death in 1893, influenced all of their music and briefly helped shape the next generation of Russian composers.
 This group was named after timber merchant Mitrofan Belyayev, an amateur musician who became an influential music patron and publisher after he had taken an interest in Alexander Glazunov's work.
 By 1887, Tchaikovsky was firmly established as one of the leading composers in Russia.
 A favorite of Tsar Alexander III, he was widely regarded as a national treasure.
 He was in demand as a guest conductor in Russia and Western Europe, and in 1890 visited the United States in the same capacity.
 By contrast, the fortunes of the nationalistic group of composers known as The Five, which preceded the Belyayev circle, had waned, and the group had long since dispersed; of its members, only Nikolai Rimsky-Korsakov remained fully active as a composer.
 Now a professor of musical composition and orchestration at the Saint Petersburg Conservatory, Rimsky-Korsakov had become a firm believer in the Western-based compositional training that had been once frowned upon by the group. Teatro Bellini, Naples
The Teatro Bellini (Bellini Theatre) is a private theatre and opera stage located in the centre of Naples on the Via Vincenzo Bellini at the corner of Via Conte di Ruo.
 It is across the street from the Academy of Fine Arts of Naples. Catania–Fontanarossa Airport
Catania–Fontanarossa Airport (Italian: "aeroporto internazionale Vincenzo Bellini di Catania-Fontanarossa" , English: Catania International Airport) (IATA: CTA, ICAO: LICC) also named as Vincenzo Bellini Airport, is an international airport 2.3 NM southwest of Catania, the second largest city on the Italian island of Sicily.
 It is named after the opera composer Vincenzo Bellini who was born in Catania. Marino Faliero (opera)
Rossini had influenced the management of the Théâtre-Italien to commission works by the outstanding Italian composers of the day—Donizetti and Vincenzo Bellini.
 Both wrote operas for that house in Paris, Bellini's contribution being the hugely-successful "I puritani".
 Donizetti's opera, which premiered on 12 March 1835 (a few months after "I puritani") was not nearly as much of a success.
 However, it marked Donizetti's first opera to have its premiere in Paris. Vaga luna, che inargenti
"Vaga luna, che inargenti " (Beautiful moon, dappling with silver) is an arietta composed by Vincenzo Bellini to an anonymous Italian text and dedicated to Giulietta Pezzi.
 It was published in 1838 by Casa Ricordi in "Tre ariette inedite " along with two other Bellini songs, "Il fervido desiderio " and "Dolente immagine di Fille mia ".
 It was also amongst the fifteen Bellini songs published by Ricordi under the title "Composizioni da Camera " in 1935, the centenary of the composer's death.
 Composed in the bel canto style, it is a frequent recital piece, and has often been recorded.
 Its original key is in A-flat major with a tempo of andante cantabile. Valery Kritskov
Valery Kritskov is a Russian conductor who used to take conducting lessons at the Moscow Institute of Culture which were taught by Kirill Tikhonov.
 He graduated from there in 1988 and then worked in Moscow-based Helikon Opera till he got employed with Novaya Opera in 2002.
 While there, he conducted many operas including Nikolai Rimsky-Korsakov's "The Snow Maiden" and "The Tsar’s Bride" as well as Anton Rubinstein's "The Demon" and Tchaikovsky's "The Maid of Orleans".
 He also conducted works by the Italian composers such as Pietro Mascagni's "Cavalleria rusticana" and Ruggero Leoncavallo's "Pagliacci" and German such as Richard Wagner's "Lohengrin" and Strauss' "Die Fledermaus" as well as a concert dedicated to Vincenzo Bellini.
 Besides operas, he is also known for his conducting of the Russian ballet based on works by Tchaikovsky and Sergei Prokofiev as well as German and Austrian ballet composers such as Ludwig Minkus and Charles Gounod.
 Later on, he became a conductor of the Coppélia ballet which was based by Léo Delibes work and was produced by Imperial Russian Ballet.
 Currently he has two CD recordings called "Chorus of the Novaya Opera Theatre of Moscow" and the "Soloists of the Novaya Opera Theatre of Moscow".