How to configure Grub to show only splash-screen and error messages during boot and shutdown?

Solution 1:

Try installing and configuring :sudo apt-get install startupmanager.

For changing the grub splash image have a look at this post.

There's also a plymouth manager. On Nvidia & ATI cards you might want to try a fix script.

Lightdm background:

sudo apt-add-repository ppa:claudiocn/slm
sudo apt-get update
sudo apt-get install simple-lightdm-manager

All I've heard of for shutdown is to comment out the following line (i.e., add # to the beginning of the line) in /etc/init/rc.conf:

#console output