Ah, OK. I see where things are now. Much clearer. You're fine for disk capacity, at least for an experimental install.
Gotcha. I suspect that your BIOS is emulating your keyboard as PS/2 rather than USB. You might be able to tweak this in the BIOS, but take a look at
this in case you can't; it may be of some help.
I seem to recall that there were versions of OS X way in the dim, distant past that had PS/2 support. I don't know if that got pulled out at some point, but it wouldn't surprise me if it did (or if it only ever supported PS/2 chipsets and devices that were Apple-blessed). ADB support was definitely in there, but that's nothing to do with PS/2.
If you can check out the stuff above before doing a reinstall, you might be able to save yourself that headache. Just sayin'. If your keyboard is emulated as PS/2, though, I suspect you're going to have the same problem regardless of which distro you try unless those kernel extensions are included as part of the installer (and loaded at install time).