Are the LH gates in A-east or A-west? There is a shuttle from F10 to A1, and if the gates are in A-east, then there is not that much walking involved; it is a much longer walk to get to A-west. With respect to your other questions, it is quite straightforward to redeposit bags after clearing customs. I have no idea about TSA regulations about locking the bags at this point though. There is I believe a separate line for security after immigration (at least that is my experience at A-west). Other folk who do a lot more international travel can clarify.