Yes, you will be significantly involved in world/story creation. The Masters will give you one starting "mission", and from there, I'm going off your choices, with my overarching plot in mind in the background. But how that plot gets worked into the actual IC campaign will also depend a lot on what you all choose to do.
It's meant to be a low-magic campaign, but crafting things like potions, scrolls, the occasional alchemist's fire, and so forth will probably be fine. I've always considered alchemy to be fancy chemistry anyway, and it wouldn't be significantly affected by changes in magic in the world. I'll probably put pretty significant restrictions on crafting magic items, so if anyone was thinking about taking those sorts of feats later on, please talk to me first. I am planning to have official IC down time on occasion, so there will be opportunities to craft.