I tried a version of this idea over the winter. Last year, I dug deeper trenches to make high rows in one section of my garden. I didn't like these awkward, deep trench paths, but didn't want to redistribute all the soil, so in these trenches, I added table scraps, garden debris, leaves, logs and covered with some upside down sod. I topped it all with straw and now its my slightly mounded hugelpath. My thinking is, it's like hugel trench composting. I didn't add any biochar or clay shards, but I have clay soil, so I hope all of this compostable material will be synergistic with the clay.
