Two dummy mistakes in case anyone else has this issue.
Don't read the internet.
In either .xinitrc or .xsessions, the command to launch xfce4 is: "xfce4-session"
Some recommend "startxfce4" - this is not correct.
must be in /etc/x11/xdm/Xsetup_0 (or whatever Xsetup file you use) or things will not work correctly.