How to use x11rdp to connect to a session started with xvfb or xvnc?

Question

X Window System

Good afternoon.
My task is to set up selenium testing in a container, and something I have already got completely confused in technologies and implementations.
What do you need?
It is necessary that the session starts at system boot so that selenium tests can run in the background . It is
necessary to be able to connect via rdp to see the run cycle.
What is done?
Installed ubuntu14.04 + x11rdp + xfce4 + xvfb

sudo apt-get install xubuntu-desktop xfce4 xvfb 
git clone https://github.com/scarygliders/X11RDP-o-Matic.git
cd X11RDP-o-Matic
sudo ./X11rdp-o-matic.sh --justdoit
echo xfce4-session >~/.xsession #изначально ставилось startxfce4 - заменил так как во многих гайдах пишут
# if screensaver hogs the cpu
echo 'mode: off' > ~/.xscreensaver

I tried to replace the connection in startwm.sh. /etc/X11/Xsession on startxfce4
What's running now? It starts, gets display 10, and after a reconnect, it gets back to display 10, ok.
If at system startup, before starting selenium, execute any of the commands to start the shell in the background:

#Xvfb :10 -ac -screen 0 1920x1080x24 > /dev/null 2>&1 &
#Xvnc :10 -geometry 1920x1080 -depth 24 -bs -ac -nolisten tcp > /dev/null 2>&1 &
X11rdp :10 -geometry 1920x1080 -depth 24 -bs -ac -nolisten tcp -uds > /dev/null 2>&1 &

Then in this case, after the reboot, the background one takes the 10th display, and we will already connect to the 11th display!
Colleagues, can you understand what I'm doing wrong?