Hi,
Ubuntu 14.04 is known to cause problems. Try with Ubuntu 12.04 which has been verified to work. I do not know of anyone who has successfully built the BSP using 14.04. If you do let us know.
Now as JP_Montero pointed out you are using an outdated version of the firmware (0.7.5). The current version available is 1.0.x and all the previous ones are no longer available.
To sum it up you need the newest version.
Get the newest arduino IDE from the downloads page and update your firmware {This step is crucial}
Build the BSP by reading the updated manuals also available on the downloads page. There are patches for ssl and UART that you need to apply.
To change the kernel configuration, once you have sourced the enviornment { OR before you issue bitbake image-full-*}
Type
bitbake linux-yocto-clanton -c menuconfig
This will give you a GUI menu to configure the kernel options. The cfg file is called quark.cfg
Change whichever options you want.
Then run bitbake image-full-* to build the image with your custom kernel.
Regarding the EDK firmware build, I do not have much of an idea. Did you double check your downoad?? Let me know how you fixed this issue.