Now if someone who knows can answer question 3 I'll be all set! How are devices enumerated in bfgminer and then MultiMiner? Is the first device shown on a bfgminer -S opencl:auto -d? considered device 0 or the last possible enumerated device?
Since you have the following in your arguments:
-I 20,16,13
You can look at the Intensity column and see the order. They should be in order unless there is an ADL / OpenCL mismatch.