I feel your vote is too long to be a decent introductory statement, and not fleshed out enough to be a decent full explanation.
And I think that Hannz's vote is completely devoid of introductory statement, and basically drops the big reveal in Sayaka's lap out of nowhere with no attempt to soften the blow or provide context, on the assumption that we'll be able to talk her down after the fact. I think that's a potential disaster.
[x] I hope everyone saved room for ice cream!
-[x] Offer everyone ice cream.
[x] Play with Nagisa until Shin comes to pick her up.
[x] Offer everyone their pick of the leftovers.
-[x] Make sure that Homura takes some. They can stay fresh in her shield forever, and she should have something to eat besides instant noodles.
[x] Ask Sayaka if we can talk with her after she's done taking Kyousuke back.
-[x] Create privacy construct and let Mami and Homura know that we think this is probably the best time to tell Sayaka about Oriko. If we keep putting it off, Kyubey might tell her to try and turn her against us. Are they okay with that?
--[x] Find a private setting to talk to Sayaka.
[x] There's a magical girl named Oriko. Her power is precognition. She sees the future. And when she foresaw bad things happening in the future, she tried to prevent them. But in the process, she wound up hurting people. She convinced herself that the only way to save somebody's life was to break their arm so they couldn't go where the danger was. I couldn't accept that, so we were enemies right from the start.
[x] One day Oriko went too far. She decided that the best way to prevent a vision of someone dying was to do something that hurt a lot of people. I was
furious. We went looking for her to take her down, and we found her. The three of us against Oriko and her girlfriend, Kirika. It was an ugly fight. I broke Kirika's leg and she broke my arm. Homura nearly decapitated Oriko with a machine gun. But magical girls can survive anything if their soul gem is intact. We put Oriko back together and made her explain why she did what she did. I was so angry. I threatened to do some pretty awful things. Part of me wanted to kill her. But, I... I just couldn't. What she did was... completely wrong and ill-conceived and caused way more harm than it needed to, but she thought it was the only way to save a life. She's... not evil, really. Just misguided.
[x] So I spared them. They're basically under house arrest. Confined to Oriko's house and not allowed to leave unsupervised, until further notice. That's their punishment. They've even been helping us, to atone for what they did. Kirika was a big help when we stopped the fighting in Ishinomaki and Sendai, and Oriko's predictions helped us save a lot of lives. That night the witch kissed you... we never would have known if she hadn't warned us. She saved your life that night.
[x] Sayaka, the thing she did that made us so angry that I almost killed her, the reason that this has been so hard to tell you... is because she's the one who burned down your apartment building. I'm sorry.
EDIT: Added checking with Mami and Homura before proceeding.
