Are the DNGs somewhere else in your LR Catalog so are not being seen as new? Did you accidentally do a Move instead of Add type of Import so LR has moved them to a different location as part of the Import?
Find the files on your hard-disk, make sure they are where you expect them to be, and see if their size is relatively consistent or if they've been corrupted, somehow.
If they are where there're supposed to be on disk then go to Library, select the All Photographs collection, press the \ (backslash) key if necessary to show the filter bar along the top, then change the filter type to Text and change the Any Searchable Field to Filename then type part of one of the filenames that seems missing and see if LR can find the file in your Library folders somewhere.
Yes I can edit the 63 images that are in the catalog for that folder in develop mode.
I am using the latest LR CC 2015 on Windows 8.1 Pro
I have two copies of the files so that must have been what happened to my edits. It still does not explain why I can't import the rest of the images but since I was able to find what I am looking for I am going to call it solved.
Thanks for your help!