boot - Lubuntu 16.04 PowerPC install failures - how is this error possible?

I'm trying to install 16.04 onto a PowerPC G5 Mac. However, this has not gone smoothly, and after hours of research and watching tutorials my problem has become maddening.

In short, every time I try to run the Lubuntu installer I end up with a screen that looks like this:

https://oi1320.photobucket.com/albums/u525/artaxerxes131/Lubuntu%20Problem_zps7xyx10qx.png

This screen is generated after I run yaboot, and after the blue lubuntu loading screen runs. What's really interesting to me about this screen is that you'll notice in the bottom left hand corner it looks lot like the OS10.5 background, dock, and Finder have all gotten mixed in there. I'm really not sure how those could be generated booting from a Lubuntu install disc. This has me very, very confused.

My machine is able to recognize the install disc and boots from it, but once I'm past the command line phase (from my reading I'm pretty sure that means I'm running yaboot?) it does not matter which config options I select - I always end up with the above screen, or a similar variant. Live, live-video=ofonly, live-powerpc, etc: all end up with the same result. I've tried different PowerPC versions of Lubuntu and several alternate installs of 16.04, but they've yielded nothing. At this point, I'm baffled.

I know installing Lubuntu is possible, but nowhere have I come across an error similar to what I'm seeing. I know errors in video seem to be common (having everything go white and fail to initialize appears to be the most prevalent (see here,and here, and here) but what I'm encountering seems different than those issues. Maybe it isn't, though, so I'm asking for any insight the community has.

So far, to fix this I've tried several things:

1. Running various PowerPC versions of Lubuntu (16.04, 12.02, etc.)


2. Grabbing several of the alternative installers for each


3. Adjusting the video settings, including:
   =nomodeset,
   video=TV-1:d video=TV-2:d (as described in the parameters section here),
   nosplash, and others

But I'm still stuck. I'm raising the white flag, since this seems to be a problem that's out of my league. Any and all advice would be gratefully appreciated.

Specs:

Model: Power Mac G5, PowerMac 7,3
OS 10.5.4
Processor Speed: 2.5Ghz
Number of CPUs: 2

Memory: 512MB
GPU: Nvidia GeForce 6800 Ultra
ROM Revision: 2119