I see some plugin and folders refuse to go away from the content folder despite the fact i deleted them in plug in. Do i need to delete them with FTP after? Will there be any database or other code record left after them?
I've had to delete some folders from file manager because deleting theme from ftp would not work. If you have subdomains created or addon domains registered with your main hosting account then there will have to always be a subfolder available in your file structure and no matter how many times you delete them they will reappear, unless you de-assign the domain names and delete the sub-domain profiles.
After deactivating a plugin, ts safe to delete the plugin name folder. But other folders created by that plugin maybe risky to delete.
Best is deactive and Uninstallation via admin will remove all installed files and folders, and database too. good luck