Welcome aboard I'm a former Zaurus user too, and feel the same way about the NIT.

I had the same experience with LCARS even after uninstalling it all. Try dpkg --purge perhaps? I reflashed my device to Diablo (upgraded from Chinook). This solved the problem.

The splash screen is handled by the package osso-systemui-splashscreen. This contains a library called /usr/lib/systemui/libsystemuiplugin_splashscreen.so at some point this says /system/systemui/splash/bootup_image
/system/systemui/splash/shutdown_image
/system/systemui/splash/window_priority
splashscreen_open
splashscreen_close
/tmp/bar.gif
/tmp/foo.gif
load image failed for %s

So I fired up gconf. Here I find 3 entries which are all 3 found in /usr/share/icons/hicolor/scalable/hildon/

bootup_image=qgn_indi_startup_nokia_logo.png
greeting_image=qgn_indi_nokia_hands.jpg
shutdown_image=qgn_indi_startup_nokia_logo.png

I don't know if LCARS changed these values, or if they replaced the pictures. I hope the former, and the fact it doesn't fix this when the package is removed is a bug IMO, but it might be this bug.

So you may try to grab the original files. I don't know in which package they are, and I don't know how to figure this out (as I lack apt-file and packages.maemo.org doesn't have the option).

Here is a howto how to change your bootup image.