What is the best approach to repair outside cantilevered wood deck joists with dry rot?
The method you found in the This Old House article - treating the rot in the original joists and adding new joists - is pretty simple stuff.  I am pretty sure the author of the BayAreaContractor.com is well aware of that option for repair.  It works fine with joists supported at both ends of the span.
I agree with that article - that it's a much more complicated job with cantilever joists, and to make a structurally sound retrofit repair is really tricky.  You can't simply repair the cantilever portion.  You're going to need a very capable contractor to pull this off without risking an unsafe deck and without doing further damage to your house.