Now, my question concerning the USB malware possibility: Is there any chance that the USB could have carried the paper wallet (that I created within armory in the offline computer) or keys of the original wallet from the offline computer to the online computer?
If you assume an unlimitedly powerful hacker then yes.
However, the security assumption is that your offline computer is safe. In theory, the OS could have been corrupted when you downloaded it.
The advantage of the offline computer is that there is only one moment that it can be compromised (at creation). After that, it is safe.
However, if the offline computer auto-runs usbs, then there is a risk every time you plug in the usb.
Ideally, an "Armory" version of linux would have auto-run guaranteed to be disabled.
There are also suggestions for doing things like using the speakers to transmit data via sound signals.
