(1) I'm not entirely sure that the logo screens are eating up your resources. However, you can try this anyway
(2) Although I haven't tested it (and really have no means to), I think you could try 'removing' the logo by using an invalid logo screen. Simply make a new text file in your C: drive (C:\New Text File.txt) and rename it to "LOGO.SYS" (so you'll have c:\LOGO.SYS). I'd think that this 'empty' logo.sys would show a blank screen.
In Win98, if you don't specify a custom logo, it will use the default logo embedded into "io.sys" (which you should NEVER modify/delete.)
If indeed the logos eat up resources, then the Shut Down screen probably wouldn't even matter. If your computer is shutting down, then your computer has freed up 100% of the resources once it finally shuts off.
- rp