Currently I am using a Lop Import sop to import some geometry scattered/instance in LOPs, which I want to export through our studio's sop layout publisher.

I need some primvars such as the Local Transform (T,R,S) of the prototypes plugged into the LOP instancer to make it into sops. Is there a way to do this? When using the LOP Import sop, and Unpack USD, I am unable to transfer the Local Transform attr which seems like some kind of Intrinsic attribute.

I'm assuming I need to create a custom primvar in LOPs that pulls values from Local Transform, then pass that through to my LOP Import sop?

It seems like the full "local to world" transform is the only one available through the intrinsics (in spite of all the different intrinsic names - packedworltransform, packedlocaltransform, usdLocalToWorldTransform - they all hold the same value). If that's the value you want, you can extract the intrinsic to a SOP level attribute with a wrangle:
4@lxform = primintrinsic(0, "packedlocaltransform", int(@prim));

Otherwise yes, you'll need to create a USD attribute in LOPs so you can explicitly import it into SOPs.

Finally got back around to this.

Did the job for me!