It's hard to say without analysing Harry Potter and the Order of the Phoenix in detail, but I'd suggest that most, if not all, of that outline is part of the same Grand Argument Story. Most of it being OS, with the "Snape / Harry + father" column being mainly IC, and both the Prophecy & Cho/Ginny columns containing a lot of MC.
But again, hard to say for sure. Maybe there's a sub-story that includes Ron & Ginny's relationship (not really shown on that outline but a big part of the book) as the RS? Maybe the Hagrid & Grawp stuff is a substory?
For writing, I'd suggest to work from a main storyform (however that best suits your process), and not worry too much about sub-stories at least in the first draft. I finished a big science fiction draft last month and was surprised to find afterwards that there were two sub-stories, each with full storyforms that I was able to find. Neither was planned, and one of them I didn't even suspect was there until it resolved!