Welcome to the forum!
I'm not very knowledgeable about key shortcuts. Here's what the manual has to say:
http://tavmjong.free.fr/INKSCAPE/MANUAL/html/Customize-Files.html#Customize-Files-Shortcuts. And you can also find info in share/keys/default.xml which is in the folder where you have Inkscape installed (I think).
However, if I understand what you're asking, I don't think that's how customizable key shortcuts is meant to be used. Do you mean that you want to assign all the symbols of a particular (symbol) font, each one to its own key? So that you can type with that font? That's how the Text tool works. You would just type a little text, with Text tool, the find the font in the dropdown menu from the Text control bar, and select it. Now you'll be typing with that (symbol) font, using the Text tool.
If that's not what you meant, would you please provide a little more info?