Assembly datums don't apply.
These would be assembly revolves/holes/extrudes defined in an assembly.
I don't know the best way to find them. If the assembly isn't too big, just look thru the model tree for a feature that is in an assembly. The one in the image below that is highlighted yellow is the actual assembly cut (hole feature).
The one highlighted in red is how that assembly cut shows up in a part that the assembly cut actually cuts.
You can also use the FIND tool, use Look for : feature, Look by: feature, Attributes: Type, Criteria: Value =Assembly Cut (see image below). It shows the parts affected by the assembly cut.
Hope this helps
Use the search tool in an assembly containing the part of interest. If there is a structure of subassemblies you will have to modify the search protocol as needed.
In this trivial example there is a single solid geometry feature created in the assembly (hole1) which intersects all three plates. The search tool example shows how to find any feature with solid geometry within the assembly (note that the search is constrained to the assembly only). You can build and save search queries if you need to do this repeatedly on multiple assemblies.
This example query is based on your statement that other than datum features you do not use assembly features so by finding features with solid geometry that should find any feature affecting geometry of components within a given assembly.
