A. - As long as you can control the drive letter assignment, you can install the Full version on a stick (I have done that with several versions)
B. - I "think" you can just copy the control panel in (and its files).
C. - The Lite version is missing a lot of stuff. The problem you alluded to has to do with the need for a fully configured path/environment (as I tried to point out in the first post.) The devlopers didn't consult with me on their decision how to configure it (USB version).
"XAMPP Lite" s an additional extra small XAMPP edition. Configured with relative paths you can use it on usb devices.
Perhaps Altrea will have some other insight, and I'll send a link to the "chief wiz"...