Hi Wovyn, welcome to the community anf Galileo!
I would definitely recommend you to upgrade the firmware to the version included with Arduino IDE version 1.5.3, following the instructions in the Galileo Getting Started guide. You won't miss them, it's mentioned everywhere, even on the paper quick start guide in the box, IIRC. That would fix a couple of things like booting off SD card and some other.
I'll let folks answer the question whether specifically version 1.0.0 of the firmware is needed for the Debian image (I've not tried the image myself yet to be sure), but as far as this one is concerned:
Also, when reading various posts I saw that Alex_T had pointed people at this link: http://alextgalileo.altervista.org/images/1.0.0/
Are these also Linux builds? Same? Different?
The image you'll find by following that link is the same as distributed by Intel as "Galileo SD card Linux image", just newer version (based on Quark BSP 1.0.0 vs. 0.7.5, the former one is the latest released, but not yet officially supported).
That's also Linux, just not Debian, but a different distributive, so to speak - Yocto's (which is a framework for building Linux distros, in a nutshell) Poky reference distribution (something they include within Yocto to make it easier for people to start building their own distros).
Hope that clarifies it If not - feel free to ask further.