I downloaded LCARS-Desktop GDM (Widescreen) from LCARS-Desktop GDM (Widescreen) - Gnome-look.org
Will this work in Elive? Would like to learn how to change the login screen and system loading/shutdown screens.
Elive uses "lightdm" as login screen ... which leaves you with the option to replace it with "gdm" (or "entrance") or to customize "lightdm" to your tatste.
For customization see https://wiki.debian.org/LightDM
And for a greater choice of themes:
How to change the LightDM theme and background? - LinuxForDevices
Not the best advice, though, as if you look at the date of the linked theme, it's a 15-year-old GDM theme.
Highly probable not, even if you would replace LightDM with GDM.
That wouldn't be a hard thing to do—make something similar to the linked theme—but I would take SLiM display manager because it is pretty easy to customize.
Even if, maybe better you let it be for good, as your Elive might end up like this:
Thanks for the link! Will attempt implementation when I get home to my daily driver.
Worry not, am going with the LightDM Solution and link to Debian.
Not sure what you meant by that but if the images below this comment are of a themed Elive, I like it! How was it done? Are there any bugs drawbacks?
That is the "Lcars" theme which is available as a pre-installed theme for E16.
You don't necessarily have to run it to have "lightdm" use the theme as a base .... it just has to be installed to enable "lightdm" to use that theme in it's configuration.
There is a lightdm-gtk (that's the one on Elive) settings manager available:
lightdm-gtk-greeter-settings/stable,stable 1.2.2-5 all
settings editor for the LightDM GTK+ Greeter
A simple configuration utility for the LightDM GTK+ Greeter. All configuration
options available in the greeter are exposed and easily manipulated using
this
Just install it with "api lightdm-gtk-greeter-settings". 
Happy customizing and do keep us informed about your adventures.
And remember:
If you're unsure, then reboot into "impermutable mode", customize and muck about all you like because when you reboot to "normal" afterwards .... you'll be back where you started. Nothing lost, nothing gained. 
Just keep some notes of what worked and what didn't for you, that way you can then safely customize for keeps in the "normal" mode.
Got E: Unable to locate package light-gtk-greeter-settings.
then update the repos (and do an upgrade too) with "apug"....always do that after an install.
Or if you're in a hurry:"apui lightdm-gtk-greeter-settings"
I must be worried when I read your questions and comments here.
I did tell you to try it with SLiM for a reason. 
LightDM is not a great idea.
Application "lightdm-gtk-greeter-settings" would allow you to move the login mask around or to add, remove, or move some elements.
One could also replace the wallpaper and change the color of the login mask by applying the LCARS GTK theme, but SLiM is much easier to customize and would help to get a better LCARS look and feel.
Liking unusable isn't forbidden, and I posted the screenshots exactly to show you the drawbacks.
Yes, it is a themed Elive. I'll add a few additional screenshots later.
Well, yes, it is the e16 Lcars theme, but not only. Beside the LCARS wallpaper, I also added the LCARS GTK, LCARS icon set, Fusion cursor, and SLiM login screen.
@endarkenment : was about to download SLim but saw this:
The SliM project has been abandoned (last release was 2013), and is not fully compatible with systemd, including logind sessions. Consider using a different Display manager or startx.
I see what you mean. @triantares Did the LightDM-GTK-Greeter-Settings thing and it works well enough. The top menu bar is still there though I can delete it. I used the same back, but I used the TOS Delta (yeah, I know, anachronism). Would like to know how to create my own actuators/buttons for Login, Restart and Shut Down.
@endarkenment Did download SLim but don't know how to invoke it from the CLI.
Next thing is to change the boot screen and shutdown screen. Do the screens have to be animated .svg files? Not daunting but would appreciate ANY advice. If this needs to get bumped into a new topic, please do so. Thanks again.
Those two are GRUB related and need changes in there.
I'm in. Will try to do initial research before asking for more assistance.
As a first, cast an eye in "/boot/grub/themes/" and do look up how to get to the nitty gritty.
From Grub2/CustomMenus - Community Help Wiki
Menu Creation Background.
GRUB 2 constructs the menu via a series of scripts, with each script building a portion of the menu. These scripts include /etc/grub.d/00_header and /etc/grub.d/05_header. The GRUB 2 menu configuration file (grub.cfg) includes section remarks showing which script is responsible for creating the section. The /etc/default/grub file contains most of the user-defined variables such as display time, menu resolution and default menuentry. Most custom menu users will want to allow these components to continue to operate normally.
The two scripts which actually place items into the menu are /etc/grub.d/10_linux, which locates kernels in the default Ubuntu partition, and /etc/grub.d/30_os-prober, which builds entries for operating systems found on other partitions.
For information on these files/folders please refer to the Grub2 page.
Strictly speaking, you would be right, but since you're missing the point, you end up being wrong.
SLiM is old, but it does let you change the session and log in.
If SLiM should be avoided, the same goes for E16 (and E25, BTW), Xorg, Debian, etc.
However, the point here is that we are not talking about an efficient environment for serious usage but about having fun.
Elive with buggy and inefficient E16, based on "the biggest collection of abandoware" in the Linux Universe (=== Debian) and themed to look like what was probably the worst GUI design ever made, is just a playground for those with too much time.
And then, there is the question of what is better: to use something new but utterly broken and unusable (e.g., Thunar), or rather, to use some old and unmaintaned abandoware that beats it in almost any respect (e.g., SpaceFM).
Thunar can't even keep its layout properly, but hey, recently it finally got the possibility to divide the screen in two halves. Yeay! Who cares...
Grub starts, and Plymouth continues until the Display Manager takes over.
Will say, one needs to modify the bootloader (BIOS and/or UEFI), boot screen, and login screen.
What format it needs is simple to find out if one looks in the appropriate folders of the components to change.
Slightly less old than E16 (and Lcars) indeed. 
Exactly.
For @ZRVoyyd I did start a short Howto/tuto on customizing E16 here: Tutorial on handling E16 by customizing the desktop
Maybe there's some pointers there too.
BTW, aprops SLiM; it might be old, but it looks better than anything else around.
Example:
https://github.com/adi1090x/slim_themes
https://github.com/Fausto-Korpsvart/SLiM-Themes
https://github.com/aufarijaal/slim-display-manager-themes/blob/master/README.md
