In the video below we show how to group pages 6,8 and 10 together into a collection of pages, and then georeference the first sheet using Scalebar, and the second and third sheet using multipoint to the first sheet using Vector Snaps in the PDF Page and the Target location PDF Page.
We also show how to extract the linework from the first Page and then georeference page 2 and 3 to the first page using CAD linework Snaps.
The two methods should result in the same accuracy of overlay because both are using the same snap locations - once in the PDF and the second time to the CAD lines extracted from the PDF.
Video shows you how