I guess it's not clear to me exactly what the problem is, the files are not missing, you can find them and work with them.
If the photos are not in the desired order, you can sort them using View->Sort
Sorry, I wish it was that simple.
To elaborate, none of the missing photos will show up in the Library until I search for it's specific filename. Only then does it show up in the Library, and in the wrong order. In order to edit all the missing photos, I would be individually searching all 400 or so missing file names.
I'm also befuddled as to why 500 of my photos would import with 1/24/2015 in the metadata, and half of them would import with 11/24/2014 in the metadata. They were all taken on the same day!
If you are having trouble finding the photos, you can sort the photos in the proper order (whatever order you want) to make things easier to find. What happens if you sort by file name? You can also use metadata to make photos easier to find.
I do not know why the dates are different.