but did Angela look like she was in control and menacing people via dreams to anyone in this episode?

Not to me. She seemed more like she was barely holding it together.

As for Nathan: I agree with all your points. I think there is no way he would do this on his own accord, neither as the killer nor as someone who supports the killer - he is way too lethargic to be thinking about avenging himself on the people who were involved in Plan Blow Up NY, and even if he weren't, Kaito was one of the people who didn't want the bomb to explode, so why should he support killing him?

And while I do think it's pretty likely someone made him plant the pictures, I don't think that same person made him throw Kaito off the roof, because, as you say, Kaito recognized the attacker and from the way he said it had to be one of the founders.

Lastly, I might be overthinking this, but I have quite a track record with mysteries, and while first suspects are not always innocent, they are in most of the cases - and Nathan is just presented a little too obviously as someone who might have motive, opportunity, and convenient blackouts.