How to delete spurious Apple Mail mailboxes and folders showing in Finder?

How to delete spurious Apple Mail mailboxes and folders showing in Finder?

After restoring Apple Mail malbox (having previously lost many messages) from Time Machine backup (having many messages including the lost ones) just selecting such mailbox in Apple Mail and then "Time Machine - Enter Time Machine" in Apple Finder menu bar, the lost messages were restored, albeit not in the original mailbox, but in other with the same name inside a new mailbox named "Time Machine", which later on was automatically renamed as "com.apple.Mail.Backup" (showing at the bottom on mailbox list pane, on left of Apple Mail three-column interface. So, I moved such recovered messages to the original mailbox and deleted "com.apple.Mail.Backup" mailbox in Apple Mail.

1. Yet, Finder still shows such "com.apple.Mail.Backup.mbox". How to delete it?

Note: Finder path above corresponds to "/Users/~/Library/Mail/V4/<weird code name here>/com.apple.Mail.Backup.mbox

2. Finder also shows several "Data_Rebuild" folders besides "Data" folder inside mailbox. How to delete such "Data_Rebuild" folders?

Note: Finder path above corresponds to "/Users/~/Library/Mail/V4/<weird code name here>/PEOPLE.mbox/Name Surname.mbox/<weird code name here>/Data_Rebuild".

3. While trying to recover the lost messages, I created extra mailbox in Apple Mail with the same name as the original one but adding 2 to the name. Eventually I deleted it in Apple Mail, yet shows in Finder. How to delete it?

Note: Finder path above corresponds to "/Users/~/Library/Mail/V4/<weird code name here>/PEOPLE.mbox/Name Surname2.mbox

macOS 10.12.6.

Thanks.