How to install XFCE desktop and remove gnome desktop?

It doesn’t appear that there’s much in the xfce4-desktop bundle. If I keep on adding other xfce4 related bundles, do they get integrated into the xfce4-bundle, or stay separately?

Why I need lightdm is that the gdm has unnecessary additional screens, a cover screen and then the login screen. How do I get rid of the gdm login? Or get rid of the cover screen in the gdm login?