Can inputs to a transaction have different values for sequence? I noticed that the sequence field is used to signal opt-in RBF. I would think that signaling RBF applies to the full transaction rather than particular inputs.

If my transaction has two inputs, and I signal opt-in RBF on one of these inputs, am I still signaling that my transaction might be replaced? Or do I need to signal it for both inputs? Is it valid to signal RBF on one input but not another? Does the sequence field need to match for all inputs in the transaction?
According to BIP 125:


  A transaction is considered to have opted in to allowing replacement of itself if any of its inputs have an nSequence number less than (0xffffffff - 1).