How can I frame this multi-level deck?
The second on is a better choice; in the first one, you have a lot of angles that will make it hard to carry the loads effectively. I would probably go with a 2x6 for the platform on the second deck to get your shape; that will get you 5.5" of difference in height. You could also go with a 2x8 for a 7.5" difference. 2x4 only gets you 2x4, and 3.5" is too short to meet code for a step. 

It would be good to see the beams to comment on the overall structure.

Think about lighting for the edge so that you can safely see the step at night.