G4 gives Ghostbuster's logo (without ghost) on boot.

+I'm running my G4 AGP on a second drive. When I learned that that volume needs repair, I tried to start up with my old 10.2 on the original drive. All I get is the grey apple for a few seconds, then the grey "do not" symbol.+

See Mac OS X: "Broken folder" icon, prohibitory sign, or kernel panic when computer starts
http://docs.info.apple.com/article.html?artnum=106805

+The original drive boots 9.2.2 just fine, though the Disk First Aid doesn't seem to do a good job repairing the volume. I'd like to try and use the Disk Utility on 10.2.+

Disk First Aid is for repair of the hard drive with OS 9.x. You will need Disk Utility on the OS X hard drive. Disk First Aid & Disk Utility can detect problems, but can't repair some types of problems. You appear to have some file/directory corruption. DiskWarrior can probably fix your problem. DiskWarrior by Alsoft
http://www.alsoft.com/DiskWarrior/index.html

+I tried both the original install discs of a G4 and a Macbook. Neither will boot.+

I suspect your G4 disks boot to OS 9 & don't have Disk Utility. Your MacBook install disks will only boot on a MacBook.

+I tried the Target mode, but can only see the original drive from the Macbook.+

The Target Disk mode only works on your Master hard drive, not the Slave hard drive. You could remove your current Master HD (OS 9) & rejumper the OS 10 drive to Master. Then try Target Disk mode. If it shows up in the Targer Disk mode, you can use Disk Utility on you MacBook to try & repair.

 Cheers, Tom 😉

Have you tried verbose mode?
http://docs.info.apple.com/article.html?artnum=106388
Then give us results.