In my case, I'm actually building up the controller from scratch.
I think I may have been able to answer my questions from some reading, though.
For the first question, I should be able to just invert the values presented in the graph for the given position.
For the second question, I may be able to pick any value on the graph, and apply those current values and hold them long enough for the stator flux vector to align with the nearest pole. In this configuration, once the two vectors align, I'm getting no torque, but I now know where the rotor is relative to the stator field so that I can start the correct commutation sequence. In this case, once both vectors are aligned, I can proceed into commutation with a value (from the graph) that is 90 electrical degrees offset from the previous value that I used to align the two vectors.
I could have the wrong idea about how sensored, closed-loop, control works on these motors as I look into building my own, but let me know if this doesn't make sense.