Edited to add: Import completed. All recent Scrapbook images appear to be present and spot checked older entries also contain images that I know are from Scrapbook. Any missing images in older posts will most likely be the result of the great LJ Photo Album to LJ Scrapbook transfer debacle, when quite a few LJ users reported random images missing from their collections.
Posts with YouTube videos all showing a "bad lj code" message instead of the video. That one was easy to figure out because I noticed long ago that LJ always changes the YouTube embed code to something shorter when a post is saved. Easy manual fix on the most recent ... just clicked on them on LJ, went to YouTube view and retrieved full embed code, go to edit mode in same post in DW and replace LJ shortened embed code with complete embed code and save. Video now works in DW. Not going to do this for every imported post but will do for 2016 posts over the next little while (an easy job thanks to my habit of tagging every one of them as "viewing")