The Wallstreet will run up to Jaguar or Panther/Tiger with XPostFacto. I'm not sure I'd recommend it, though. I've never had a Wallstreet, so I can't give any real advice. Depending on whether your Wallstreet has the 2MB VRAM or 4MB VRAM, I can say that it'd probably be a pretty lousy experience. Rough scrolling, jittery window movements, etc.
The G3 iBook will run Tiger decently but it'll run Panther better. The main limitation isn't the CPU speed so much as it is the VRAM. The 8MB causes it to be pretty shuddery IMHO. The G3/600MHz iBooks with CD-ROMs (not Combo or Super) are where they switched to 16MB, and while they won't run Leopard they'll run Tiger without the shudder.