Not dumb, "c-" is ambiguous, but yes – it refers to the control key, so ctrl-a will get you back to the start of the line/sentence/etc.

My ctrl key seems to mimic my Command key for most of these command and not do anything in other cases (Firefox & Word). Is there some setting I need to change?

I'm using these keybindings in Firefox right now, without any custom config (other than mapping caps lock -> control). Go to the URL bar and hit control-a and control-e; do they work? Type a few words of a reply comment, and in the comment text field, try control-a and control-e; do they work?

The shortcuts are meant for applications using readline or readline conventions (so tons of command line apps, but also lots of Cocoa apps).

Firefox and Word probably are not in that category (don't know, I use Chrome/Safari and Pages).

Neither of those programs use readline. I map ctrl-e to end of line in Word because I use it so habitually. Safari uses these shortcuts as does terminal.

yes