I like your ideas. Especially for your characters.

I was thinking for mine, the girl was an assistant to one of the scientists who worked on the development of cyborgs who doesn't necessarily like what the military has done with the technology they were given, and the boy resents the whole idea of robots and cyborgs in general, witnessing his family members become imprisoned or killed by the rogue robots? I figure that would give some conflict with your characters, which could be fun. What age were you planning on?

I think it will be something that unfolds while we move forward. We can begin like, an hour or so after the first attack took place. I was thinking this could take place in the city, where everyone has gotten completely used to technology running their lives. All of them could happen to meet when coming upon the same hideout.