There should be no data loss, but the new domain property may take a while to populate.
Note that some integrations do not support domain properties yet. Like linking to Google Analytics.
I'd not delete any site level properties. Keep them as a backup. Even consider adding the www variants.
Google AdSense doesn't currently offer hourly reports. The most granular they have is "day."
You can submit Feedback to Google from your AdSense account saying that you would like this feature. However, Google doesn't typically respond to feedback or act quickly to implement feature requests.