Schlitzohr and Arthmoor's versions of Granite Hill works together without issue, almost as if they were meant to be used simultaneously. It's just that good.

For the discerning eye, however, they would find that at the foot of Schlitzohr's Granite Hill, are NPCs that walk right into the farm house that Arthmoor adds.

The reason being that the farm house blocks off a patch of potato crops as well as a platform with which an NPC sells the crops. All these have idle markers that NPCs from both mods can't help but attempt to activate, hence the incompatibility.

This mod simply disables said crops, platform, and idles, and moves Schlitzohr's farming idle marker into Arthmoor's farm field for better integration.

Tested on a 900+ modded setup, along with Schlitzohr's other village mods, etc.

Your Load Order should be:
Granite Hill.esp
Fall of Granite Hill.esp
>>My patch

Reversing the load order of the two mods will cause a tear in the landscape right across the farm at the foot of the village.

Minor Issue:
The Mercenary added by Schlitzohr at the foot of the village may sometimes walk into walls/the guard tower's base.
I uploaded an optional file to move the merc's guard marker to someplace else in an attempt to prevent this.
You will need a new save for the relocation of the farming idles and guard marker to work.