The last lines or your file:
Warning: unused libraries in /usr/lib/lxdm-greeter-gtk: libatk-1.0.so.0 libpangoft2-1.0.so.0 libm.so.6 libpangocairo-1.0.so.0 libgio-2.0.so.0 libpango-1.0.so.0 libfreetype.so.6 libfontconfig.so.1 libgmodule-2.0.so.0 libgthread-2.0.so.0 librt.so.1 libXau.so.6 libck-connector.so.0 libpam.so.0 libcrypt.so.1 libpthread.so.0
Warning: unused libraries in /usr/sbin/lxdm-binary: libgtk-x11-2.0.so.0 libatk-1.0.so.0 libpangoft2-1.0.so.0 libm.so.6 libgio-2.0.so.0 libfreetype.so.6 libfontconfig.so.1 libgmodule-2.0.so.0 libgthread-2.0.so.0 librt.so.1
Using BuildRoot: /home/neal/src/tmp/lxdm-0.2.0-1pclos2010-buildroot to search libs
No idea what it means for a packager, but I notice that the "wanted" /usr/libexec/lxdm-greeter-gtk in /etc/lxdm/lxdm.conf is in fact in /usr/lib : I changed this in lxdm.conf, did a "killall xdm" in tty (as I got rid of gdm early this morning there was only xdm at new boot of the vm) and started lxdm:
# /usr/sbin/lxdmThat works !

Well, LXDM still doesn't appear in PCC though.
I still see only XDM in it, so I look where are the places in the system where XDM can be found. I go to /etc and grep it all:
# grep -R XDM *
Among places I find it in /etc/ati/authatievents.sh : an executable shell script. In PCC we can find atiauthevents among the services. I now try something:
* activate it in services
* create directories:
# mkdir -p /var/lib/lxdm/authfiles //because there is the same for gdm and for xdm but none for lxdm
* add a block text in /etc/ati/authatievents.sh : I copy the GDM block and write LXDM instead of GGM // don't know what I'm doing there, as I don't know bash and so on... just a guess, maybe imitating the preceeding blocks would be more relevant : no idea !!!
Now I'll try it, reboot it to see if that helps in any way. You might want to look at all what comes with "grep -R XDM *" under /etc, because I stopped at the first idea without looking at the other lines of the output.