Garden plans 4

This officially has to be the suckiest map so far

This part is about the backyard's vegetation...
OK, OK, so the map above I made by zooming in to the backyard in the south and put the future patio, and mark with bright green the area that can be planted in. But it looks so yucky so I guess I should just use pictures instead...

Seen from second floor. The patio and the garden next to it are not visible. Retaining wall at bottom

The zombie side. Our shed in center. Southern fence, the steep slope and border toward neighbor...

The backyard is pretty big, south facing and has potential.
Between the retaining wall and the patio there is a wide area where trees can be planted. I am a bit worried about the roots because I don't know what material was used to backfill the house foundation, and if clay was used roots of trees may eventually cause cracks there. But on the other hand, the ground is already full of roots...
If we disregard the roots concern, say by installing root barrier, the backyard is if trees are planted there I will have good pruning and picking access to them both from the balcony and from the terraced area above.
In that case, I would install the root barrier underneath the patio beforehand, and maybe even go back to 3 rows of tiles to make it even wider. In fact our next door neighbor has already a young peach tree in their backyard.
The terraced part looks like it will collapse any minute, and I am worried what will happen if a heavy rain falls. I am thinking about leading the water away somehow from the current terrace. The neighbor has kept their slope as it was, maybe with good reason. Ours seems to have become less stable thanks to the terrace. The slope is not small, which can maybe be hard to see even in the pictures. To give a kind of indication, the top of the slope is on same level as 2nd floor, and the fence that is seen in the picture, which looks small, is in fact real tall, over 2 meters. But maybe the length of the backyard makes it look smaller.

That's it. That should conclude my plans at least for now. Let's see how much of it will happen.