A great piece of work, would love to see a full figure. If you're interested in his life, I recommend Robert Massie's biography, he was truly an amazing character.
In your photo, the sword of the Order of St. Andrew is turned upside down with swords, but in the Russian Empire, swords on orders appeared only as a special sign of exclusively military merit only during the fighting since 1855. In addition, in the 18th century the stars of St. Andrew the First-Called were sewn, until 1800 there were no double-headed eagles on the stitched stars, and only the St. Andrew Cross was present. Peter I received his order of St. Andrew the First-Called in 1703 for the capture of Swedish ships at the mouth of the Neva. You can look at the stitched stars of st. Andrey in the photo below, including on the uniform of the guard at the time of Elizabeth Petrovna (Elizabeth of Russia). And Peter I had a similarly shaped order star.