Next Step: Step 5: Try to force a data upload
4. The Re-save trick
Once you've launched the game, made sure your settings are set to upload character profiles, and you're logged in, open the save you want to upload. Once in-game, un-equip a piece of equipment from your character, such as the helmet. Save your game with a new save. Re-equip it and save again.
I usually let the game sit there for a few minutes to give it time to do any uploading it needs to do. Then just repeat the saving with your other characters that you want to upload. The data can take a couple of hours to show up in the Keep.