Since I have many, many photographs that look almost exactly the same and in the same condition as these, I'm pretty sure that they are printed on a type of cardboard (don't know what it is really called). Anyway, the photo is printed on very stiff, thick paper. Mine have yellowed and aged in very much the same manner. All of the ones I have were done in the late 1880s and 1890s.
Yes, they look like some sort of hand drawing; but bear in mind that the quality of glass in a lens back then produced softer photos.
Just a guess. I do hope I'm right.
Janet