Hi,
1) this should be posted in MM forum, not here
2) let the person go to MIGO , to menu Settings, click Default Values and check checkbox "Propose All Items"
3) I guess if it is STO it would need goods issue first happening in source plant so that GR can happen in receiving plant (so first create Outbound Delivery in source plant, post goods issue against it and then do the GR with 101 against this delivery or PO itself)
Regards,
Tomek