Question: When was the fourth Monarch in Hawaii?

Context articles: Queen Emma of Hawaii
Mary Dominis
King Kalākaua's world tour
Kamehameha IV
Mongkut
United States Minister to Hawaii
Pōmare IV
Hayam Wuruk
Merrie Monarch Festival
List of the last monarchs in the Americas

Emma Kalanikaumakaʻ amano Kaleleonālani Naʻ ea Rooke of Hawaiʻ i (January 2, 1836 – April 25, 1885) was queen consort of King Kamehameha IV from 1856 to his death in 1863.
 She ran for ruling monarch against King Kalākaua but was defeated.
Mary Lambert Jones Dominis (August 3, 1803 – April 25, 1889) was the first mistress of Washington Place in Honolulu.
 She was also the mother of John Owen Dominis, Prince Consort of the Kingdom of Hawaii, and mother-in-law of Hawaii's final monarch Queen Liliʻuokalani.
 She is credited with starting the Christmas tree and Santa Claus traditions for Christmas in Hawaii
The 1881 world tour of King Kalākaua of the Kingdom of Hawaii was his attempt to save the Hawaiian culture and population from extinction through the importation of a labor force from Asia-Pacific nations.
 His efforts brought the small island nation to the attention of world leaders, but sparked rumors that the kingdom was for sale.
 In Hawaii there were critics who believed the labor negotiations were just his excuse to see the world.
 The 281-day trip gave him the distinction of being the first monarch to circumnavigate the globe, just as his 1874 travels had made him the first reigning monarch to visit America and the first honoree of a state dinner at the White House.
Kamehameha IV, born Alexander ʻIolani Liholiho (1834–1863), reigned as the fourth monarch of Hawaii under the title: "Ke Aliʻi o ko Hawaiʻi Pae ʻAina" of the Kingdom of Hawaii from January 11, 1855 to November 30, 1863.
 His full Hawaiian name was Alekanetero ʻIolani Kalanikualiholiho Maka o ʻIouli Kūnuiākea o Kūkāʻilimoku.
Phra Bat Somdet Phra Poramenthra Maha Mongkut Phra Chom Klao Chao Yu Hua (Thai: พระบาทสมเด็จพระปรเมนทรมหามงกุฎ พระจอมเกล้าเจ้าอยู่หัว ), or Rama IV, known in English-speaking countries as King Mongkut (18 October 18041 October 1868), was the fourth monarch of Siam (Thailand) under the House of Chakri, ruling from 1851 to 1868.
The Minister to Hawaii was an office of the United States Department of State to the Kingdom of Hawaii during the period of 1810 to 1898.
 Appointed by the President of the United States with the consent of Congress, the Minister to Hawaii was equivalent in rank to the present-day ambassador of the United States to foreign governments.
 As principal envoy of the United States government to the monarch of Hawaii, the Minister to Hawaii often dealt in affairs relating to economic, military and political matters affecting both nations.
 The Minister to Hawaii also represented the interests of American citizens residing and working in Hawaii, conveying their concerns over United States foreign policy to the President of the United States.
Pōmare IV (28 February 1813 – 17 September 1877), more properly ʻ Aimata Pōmare IV Vahine-o-Punuateraʻ itua (otherwise known as ʻ Aimata – "eye-eater", after an old custom of the ruler to eat the eye of the defeated foe), was the Queen of Tahiti between 1827 and 1877.
 She was the fourth monarch of the Kingdom of Tahiti.
Hayam Wuruk, also called (after 1350) Rajasanagara, Pa-ta-na-pa-na-wu, or Bhatara Prabhu, (1334–1389), was a Javanese King from the Rajasa Dynasty and the fourth monarch of the Majapahit Empire.
 Together with his prime minister Gajah Mada, he reigned the empire at the time of its greatest power.
 He was preceded by Tribhuwana Wijayatunggadewi and succeeded by his son-in-law Wikramawardhana.
 Most of the accounts of his life were taken from Nagarakretagama and Pararaton.
The Merrie Monarch Festival is a week-long cultural festival that takes place annually in Hilo, Hawaii during the week after Easter.
 It honors King David Kalākaua, who was called the "Merrie Monarch" for his patronage of the arts and is credited with restoring many Hawaiian cultural traditions during his reign, including the hula.
 Many "hālau hula" (schools), including some from the U.S. mainland and some international performers, attend the festival each year to participate in exhibitions and competitions.
 The festival has received worldwide attention and is considered the most prestigious of all hula contests.
The Native American hereditary leaders during this time are not included.
 Those that are listed as former monarchs of what is now the continental United States were heads of European seated monarchies (or Mexican monarchs, such as Agustín I of Mexico and Maximilian I of Mexico) and themselves never set foot on American soil.
 Others were indigenous monarchs, such as Malietoa Tanumafili I, Tuʻi Manuʻa Elisala and Liliuokalani of Hawaii; The last monarch of each state and territory may not be the last colonial ruler (i.e. Louis XV of France is the last French monarch of Louisiana, but Napoleon Bonaparte, prior to becoming Emperor, was the last ruler of Louisiana).
 Also their end of reign may not be how the US acquired these states.
 One state can have more than one last monarch, since each state may have been the product of many different acquisitions by the United States.
 Different claims of a foreign country are taken into account.