hello
If I remebre correctly, for the xd, gdm or whatever into the /etc/rc.d/init.d there is the X initialization script, I think is callled xdm, there you can change to gdm, kdm or whichever login manager you want.
for your 2nd question it seems that your system is executing kde and icewm at the same time,
Try to just execute 1.
lyx0m