Nice job on providing good details for diagnostics!!
Yes, the GPT header messages are expected until you get booted up and run through the root filesystem expansion steps documented in the wiki.The messages otherwise are not a problem, and things should work fine anyway.
The unknown messages are more interesting. It looks like it may be trying to load modules that do not match the kernel. Is there any chance that you are booting a kernel other than the 3.8 kernel that is part of the image? Booting the yocto kernel with the Debian image modules might do something like this.The fact that you are getting these messages at all probably rules out booting the 3.2 kernel by mistake..
You should see a couple of other kernel output lines that can confirm the kernel version and it's parameters near the beginning of the kernel messages.
Stuart