This may answer a question about who painted the portrait seen in the last image, but I cannot find a lead to an artist R. Davy. The closest I can find is a colorist R. Davy who lived between 1771 and about 1843.
From eBay; monocolor tint removed and exposure increased. Also posted to Duchess Augusta of Cambridge’s Subalbum here.
This print is based on the portrait seen in the last image.
Keywords: Giere, Augusta Wilhelmina Louisa, Augusta of Cambridge, Augusta of Hesse-Kassel, Auguste Wilhelmine Luise von Hessen-Kassel, Princess, Duchess, Hesse-Kassel family, Hanover family, side curl coiffure, turban, earrings, off shoulder vee neckline, pleated bodice, quarter length puffed virago sleeves, bracelets, vee waistline, wrap