Instead of using the Awesome-Markers plugin, you could follow this article on creating numbered markers in Leaflet:
http://blog.charliecroom.com/index.php/web/numbered-markers-in-leaflet
The associated Gist is here:
https://gist.github.com/comp615/2288108
An simple example of how this would work is as follows:
// The text could also be letters instead of numbers if that's more appropriate
var marker = new L.Marker(new L.LatLng(0, 0), {
icon: new L.NumberedDivIcon({number: '1'})
});