They weren’t Royal Houses: since those were Dukedoms, they can only be Ducal Houses. They were once real Dukedoms / Ducal Houses, however all 3 of them ceased to exist (as Dukedoms) centuries ago.
The Duchy of Carniola was an administrative unit of the Holy Roman Empire (part of the Kingdom of Illyria with Ljubljana as its capital). After the Kingdom of Illyria was disestablished, the Duchy of Carniola became part of the Habsburg Monarchy and was administered by locals (as per imperial patent of 1861). The duchy ceased to exist in 1918 and its territory was annexed into the newly found State of Slovenes, Croats and Serbs. Currently, the Duchy of Carniola doesn’t exist: it’s parts remain annexed within Serbia and Croatia, with a smaller part included in Italy.
The Duchy of Pomerania was a duchy on the southern coast of the Baltic Sea. It was ruled by the House of Griffins. After the last of Griffin dukes died in 1637 (during the Thirty Years' War), the Duchy ceased to exist and was divided between Sweden and Prussia (Brandenburg-Prussia). Although years later an attempt was made to re-establish the Duchy (by Bogislaw XIV Griffin, the last Duke of Pomerania), it was again divided between Prussia and Sweden (the border was settled in the Treaty of Stettin in 1653). Nearly two centuries later (in 1815) the entire territory of the former Duchy was merged into Prussian province of Pomerania. It remained part of Prussia and later Germany until the end of World War II, when it was occupied by Soviet troops and later divided between Poland and Germany. After the collapse of the GDR (in 1990), the German part of Pomerania was included in the Mecklenburg-Vorpommern land. In 1995, the Pomerania Euroregion was set up on the territory of both Polish and German Pomeranias (Euroregions are usually set up to connect historically united regions divided between states of the European Union). Most of the historical Pomerania is included in this new Euroregion (including the territories in Poland, Sweden and Germany).
Duchy of Livonia existed for 60 years only, from 1561 to 1621, with the exception of the time between 1570 to 1578, when the short-lived Kingdom of Livonia was established (during the time of the Kingdom of Livonia, the territory was invaded by Ivan the Terrible). During the times of Polish-Lithuanian Commonwealth, Livonia became a joint domain administered by the King and Grand Duke (of Poland and Lithuania) jointly. The next important phase in the history of Livonia was from 1639 to 1721, when Sweden was given the approximately the same area s the former Duchy of Livonia following the 1626-1629 Polish-Swedish War. The territory was henceforth known as Swedish Livonia and became an important part of Sweden (Livonia's historical capital, Riga, became the second largest Swedish city and one of the economical centres of the Kingdom). Sweden's rule over Livonia lasted only 100 years: according to the Treaty of Nystad (1721), Sweden lost Swedish Livonia, Swedish Estonia and Ingria to Russia. The territory of the Livonia (now known as Liflyandskaya gubernya - the Governorate of Livonia) remained within the territory of the Russian Empire until the end of World War I, when it was split between the newly founded states of Estonia and Latvia. The 1918 division was the final one and few changes happened to Livonia ever since.