What is the strongest way to join a deck joist to a corner joint?
I guess I'm curious why you wouldn't simplify the layout like this:

Yellow = deck joists

Green = support beams



Your decking would run diagonally over the joists.  If you use 2x boards for decking, that should be fine if the joists are 16" on center.  If you want to use 5/4 decking, you should probably put the joists 12" on center so that the diagonal run is closer to 16".