I see two things though that are out of place:
1. Ken's ki is orange, meaning he has Body and Heart. So, why is his role call "Amazing Ability" (Ability being Technique), and why is he placed between Jan and Retsu during the pose?
2. Gou's ki is violet, or Body and Technique. So, why is his call "Iron Will", and why is his place between Jan and Ran?
Good questions. There's no concrete answer, so I'll speculate.
Ken is Amazing Ability because he was lazy and didn't want to train seriously. He achieved KenSan when Shafu said it just fell into his lap spontaneously one day. None of the other Rangers can hope to achieve what Ken did because they don't favour his lazy methods, and they weren't trained by Brusa himself. Only Gou comes close for mastering TTPD, and that took a lot of work, work that Ken himself wouldn't be up for. His KenSan "Technique" was a spontaneous and probably one-time achievement. Unlike the cores, he can't improve himself much more, especially now that SaiDaiOh is free.
Will is not the same as Heart. Ran has a strong will as well, but she is also compassionate, and has that nurturing quality that the others lack. When Rio betrayed their friendship, Gou pretty much lost his best friend. His Iron Will arises from a ruthless disregard for other people and a selfish concentration on his personal effort in his training. He leaves his teammates behind in search of the ultimate technique. He used a forbidden Waza to try to beat Rio and got screwed up for it.
Shigeki is total concentration on the self, without the desire to conquer others, but without the compassion to aid them too. That was what Gou created 10 years ago, and he couldn't go back from it. Miki's Changer probably showed for the first time in history that Shigeki's power can also be used to defend others alongside Geki, so Gou joined them. In the end, Gou was stuck with ShiGeki so he couldn't become balanced like the triangle, and he was still selfish enough to only want the best of the best attacks.
As for their lineup, it doesn't make sense in this regard, but I don't think it's a big deal whether Gou and Ken are switched. The point is that they are inside the triangle, protected by it and fighting closer to their comrades as Jan wanted, instead of being outside it.