You won't find many KFAT files typically. You can browse through the beta files found within the TRE repository here on MTG for uncompressed versions of the animations for an easier approach. It would seem before release of the game, SOE compressed all the animations, but not before.
The numbers you're looking at, i.e. "FF FC 17 E7 " are bytes. Bytes are a value between 0 and 255, which when combined together can create values. I apologize if this is something you know, but just incase you don't: every value is made up of bytes. The most common value types you're going to find are floats (floating decimals like 4.2918), and 32 and 16 bit integers. Floats and 32 bit integers use four bytes, 16 bit integers use two, etc. Quaternions are four floats long (x, y, z, w). Which means that every Quaternion is going to be 16 bytes in length in a KFAT file. In a CKAT, I believe it's compressed down to four bytes.
Typically at the start of many nodes within IFF files, you have a single value like a 32 bit integer at the head of the file that references how many values are within that node, with every value afterward referencing the data itself.
As for matching up with skeletons, it literally is just a string match. It does look for a bone with the name being referenced in the animation, and will work on an animation in game even if the bone is not found. It's very robust in the fact that it won't crash if it doesn't find the needed bone. So if the XFIN says "chest3" then its going to manipulate any bone named "chest3." That is the only connection between skeletons and animations within SWG.
If you have more questions, I'll do my best to answer them as soon as I can. The ANS file is an interesting format and tricky to work with, but a bit straight forward when you know what you're looking at. I've done some work with ANS editing and have even been able to import some work into other games but because of my lack of good math skills, my success has been limited =D