If you prefer not to use xanthum gum (its not paleo and some people react to it) replace with your preferred substitute as outlined here. or better yet, use pixie dust. It is recommended that you use the egg if you don't use the gums.
You can use any natural form of sweetener in place of the honey if you prefer, such as coconut sugar, rapadura sugar or rice malt syrup.
If you omit the egg, consider adding a substitute such as a chia egg (1 tblsp chia mixed with 3 tblsp boiling water, left 15 mins or until cool and a thick gel forms) or a flax egg (same as for chia egg, use 1 tblsp ground flaxseed instead of chia).
Not using egg or gum results in a much denser loaf, still delicious toasted, but with a firmer, chewier texture.