I'll post again when I've got something like four or five votes in.
Just so you don't get your hopes up too high, but you getting five responses isn't very likely. People in general don't review fanfics that much, and if they just post offering suggestions to your plot without mentioning the story, then that breaks the rules of this section, and said posts will be deleted.
I'm guessing since you want to go with a choose-your-own-adventure type story, that you want to keep the choices in. But really, the CYOA stories work because the reader can always go back and see what the other decisions would have lead to. Right now it just seems as if you're waiting for others to make the plot decisions for you. What you could do is take the choices, write out what happens when a reader chooses each one, and then post/link them through the thread so that there's no waiting for votes. Plus, it seems more fun because it's not just the majority's decision, and readers can go around and see where the other choices could lead them.
As another piece of advice, you probably shouldn't have every decision left up to choice. Only the ones that really affect the plot. Ask if it really matters overall if May is saved by a Caterpie or a Weedle. If it doesn't (and probably not since "any other Pokemon" is a choice), cut that choice out, continue writing the chapter, and leave the choices up to those that have more serious outcomes to the story.
Since I'm tired and didn't expect to write a full review, I'll give a very quick and general one about your story.
For one thing, the chapter moved way too fast. You should take the time to set up the scene and the characters. Why is May out on her own in the middle of the field, riding her Blaziken? What caused the fire?
Mostly, though, why does Blaziken suddenly abandon its trainer? That really doesn't make sense for the majority of trainers, to have their Pokemon not do everything possible to stay with them. It doesn't paint May as a good person if she's telling her Fire Pokemon to get into the lake. If you were going for a character that really doesn't care about someone that she spent time with, then this is fine. But it doesn't make sense unless you mention why she made that decision in the story. Otherwise, Blaziken's choice to completely abandon its trainer comes out of nowhere and seems like a convenience to the plot. While I can figure that you wanted Blaziken to not be around for the rest of the story, there probably was a better way to do it.
I haven't looked at your brother's thread yet. But I will say that the both of you probably should spend more time working together on your story. This reads as if it was rushed because of how quickly everything moved without much set-up. Take the time to write the story and make it the best it can be.
Or, if you really like have reader participation, you could follow the suggestion of posting this as a roleplay in that section. It might actually be more to your liking than as a CYOA fanfic.