Hi,
1. You may check the concept of Transportation Management to incorporate the requirement. Through TM, you can create shipment and shipment cost documents using inbound delivery before GR. Once you transfer the shipment cost, system can create automatic PO and Service entry sheet. The cost can be posted to separate GL here. Once the GR is done, the shipment cost can be loaded to material cost as explained in the note: 427944 - Info: Shipment costs as delivery costs during goods receipt
2. Please check whether substitution rule in GGB1 can full fill your requirement. (I am not sure about it, please check with your FI team)
3. Please check LECI transaction.
Regards,
AKPT