| I also removed most of the files from Lr, because they are now located elsewhere and I don't want to use up more space than necessary. |
This is a mistake, there is no reason to remove the photos from LR. You can store the photos on any disk you want where there is enough space.
So the proper workflow is Import photos into LR, telling LR to store the photos on whatever disk has enough space and whatever folder you want the photos to be in. Edit, add metadata, etc. Do not remove the photos from Lightroom! Close Lightroom. Next time you return to Lightroom, you will find all of your edits and metadata.
Now, since you have removed the photos, the only way to get the photos back into LR is to import them again, and Lightroom will assume these are new photos it has never seen before, and they will have no edits and no user-supplied metadata.
| Now when I open Lr and want to import those same CR2 files from their new location, they are all greyed out, as are half the JPGs. |
This means you didn't really remove the photos from Lightroom, so you are prevented from importing a photo a second time. Do not import the photos a second time! You have to find the photos in LR, clicking on All Photographs, and then you will be able to make use of them.
| Under the All Photographs menu item you showed last time, the pictures look like they are there, but they're not, because I have moved them, and Lr does not not know where the photos are now stored. |
If the photo thumbnail is there, you should see an exclamation point icon in the rectangle surrounding the photos, click on the exclamation point icon and then you can direct Lightroom to the proper location of the file.
| Also I have not assigned keywords or metadata to anything. I just store under date folders - I find it easy. |
This has a major drawback. Today, you may be able to remember what date the photo was taken and go to the proper folder. But when you have thousands of photos, you will not remember the dates the photos were taken. This is why assigning keywords and other metadata is so important, the keywords and other metadata will enable you to find the photos when you are no longer able to remember the date the photo was taken.
Please take some time and read or view some beginner material on Lightroom. This will make your life much simpler. The investment of time will be well worth it.
https://www.lightroomqueen.com/quickstart/
Getting Started with Adobe Photoshop Lightroom 5 | Adobe TV
Please take some time and make changes to your workflow. Please read my second paragraph at the start of this message, please try to conform with the best-practices workflow that I have described, you will make your life so much easier and get a lot more out of Lightroom.