SkyRim keyboard mapping

if you use 1-2-3-... shortcuts to select favorites you cannot remap the 1-2-3-.. keys.

as far as I know everything else should be remappable

oh maybe Esc key and Tab key aren't, not sure. But basically everything you find in options you can set the buttons for it
 
you can set 1 - 9 keys to your favorited items by opening the favorites menu (default Q) and then hitting the number. I'm guessing same can be done over the numpad.

as far as I can tell there's no way to change that functionality in-game.

default enter key is E, you can remap it.

you can remap the default WASD "arrow keys"

if you meant something else, please elaborate on your question.