Try to remove all the "kaspersky" entries with this tool: https://www.resplendence.com/download/RegistrarHomeV9.exe
Install it, and perform a search of the text "kaspersky", then select and remove all the entries.
About locked dll and Kaspersky files in general, try to remove in Windows Safe Mode.
I will try later to do these steps.
UPDATE: before trying to remove anything manually, I just tried own KPlus uninstaller from Windows Control Panel -> Programs and features, and it went well, so maybe you rushed using the kavremover...