If this is a question for me, then I would correct the names for how it would be in the English manner of their pronunciation or how it sounds in the Russian original, because now, how your regiments are named, resembles a mixture of German transcription with erroneous Russian transliteration.
That's right:
Liflyándsky - from the name of the region Liflyándia in Russian, for English speakers it is Livonia.
Pereyaslavsky - from the name of the city of Pereyaslavl, now it is the city of Pereyaslav.
Seversky - from the name Severskaya land in Russian language (the region of Novgorod-Seversky with the city of the same name), but not from the word "sewers" in English, but Siveria or Severia in English.
Derptsky - from the name of the city of Derpt (Dorpat in eng.), at that time it was the city of Yur'yev, and now it is Tartu.
Tiraspolsky - from the name of the city of Tiraspol.
Chernigovsky - from the name of the city of Chernigov in Russian (Chiernihiv in eng.).
Arzamassky - from the name of the city of Arzamas.
Nezhinsky - from the name of the city of Nezhin (Nizhyn in eng.).
More on the uniform of horse-jaeger: Cut the uniform like a cuirassier tunic. The color of the uniform is dark green. The collar is dark green. The cut of the cuff is of the Uhlan type. Trousers are dark green, Uhlan type. Hussar-type shako with green tassels and cords. Buttons for all regiments in white metal. Cuffs, epaulettes, stripes on trousers, edging along the edge of the collar, lining of the lapels of the tail of a certain color for each of the regiments. The cartridge bag and shoulder-belt are of the Uhlan type. The belt for fastening the carbine is of the Uhlan type. Swordbelt like that of the guards horse artillery. Sabrеs for light cavalry model 1809. The swordknot of the lower ranks, like all light cavalry, are made of red yuft, without distinction by squadrons. Saddle, shabrack (saddlecloth) and all horse harness according to the Uhlan model. The officers wore silver cockades on their shakos, silver tassels and cords, silver epaulettes, silver buttons of their uniform and silver monograms A1 on the shabrack (saddlecloth), as well as infantry-type officer swordknot for sabre, also a silver officer's belt with silver tassels and stripes of black and orange silk. The supply of horse-jaeger regiments with carbines was delayed, and most likely the regiments in the active army did not receive carbines until the end of the war.
It is worth noting that all the regiments, according to the documents, received new uniforms for a period from January 1813, except for the Derptsky and Arzamassky regiments - these two regiments fought in the old (dragoon) uniforms until the beginning of 1814.
Regimental colors:
Liflyándsky - red.
Pereyaslavsky - raspberry.
Seversky - orange.
Derptsky - pink.
Tiraspolsky - yellow.
Chernigovsky - blue.
Arzamassky - light blue.
Nezhinsky - sky blue.
