Hugglekultur mount with holes for appletrees

Hi all!

My boyfriend and I are starting a food forest on our property and I'm searching for confirmation/challenges to see if our idea makes sense!

Here's some context:

We want to plant 2 semi dwarf Rouville appletree on a south facing 30° slope. I only have maximum 2 ft deep of rich loamy soil before we hit bedrock.

We also have a big surplus of felled trees that had to be removed to build the house.

So the goals here: get rid of the trees by enriching the soil AND prep the ground for the first phase of our food forest, starting with a 2 apple tree guild.

To reach an ideal 4 to 5 ft deep soil for the taproot of the apple tree I was thinking about building an hugelkultur berm roughly 40 feet long by 12 feet of width and about 2-3 feet high.
We don't want to plant apple trees directly on the hugelkultur mount to avoid root collapse and/or shearing that could happen (or so I've read) with the whole hugelkultur mound's natural decomposition progess.

So this is the part I'd like to have a feedback on:
Our current idea is to create 2 "holes" 4ft x 4ft free of log in the middle of the mount.
We would fill them with sand and dirt to plant the appletrees. Basically the hugelkultur mount around that zone would be there to keep the sand and dirt from washing away and to plant the rest of the appletree guild shrubs and herbs)
I am wondering if this makes sense? What are the potential issues you can see?

Here's a picture showing the first layer and the square zones, free of log, for one of the appletree.

Thanks!

South facing slope with a surplus of logs to use up, sounds like the setup is practically begging for hugelkultur. The one thing I'd keep in mind on a 30 degree slope is that water runs off fast, so burying the wood deep enough to act as a sponge matters more than usual. The bedrock at 2ft should be less of an issue once the mound adds height above it.