I like your thinking, but would adjust a few things based on a decent amount of
hugel experience and reading. That horizontal log will make a good base for a large hugel, but probably needs part of it cut and moved if you want to bury it more easily and beneficially. This is because for most species, if the upright tree on the left is alive, a hugel right up to its bark above the
root collar would be bad for that tree. If it is already dead, then it would wick moisture into the air, like any
wood sticking out of a hugel will do. I would cut the log in manageable lengths back to the dripline of the other tree if it is alive. If it is dead, i’d cut back a wheelbarrow’s path width between the hugel and snag, and cut the right side of the log so it pretty much all lays on the ground.
I would also just make sure you have a 1%+ slope on the path on the uphill side, to avoid building a floating dam.