The statue crying. doesn't it answer the Lawgivers question?

It's not specific. I took it as that there will still be problems between apes and humans in the future. But to what extent, who knows?

You can read the screenwriter's thoughts on the ending here: http://www.potamediaarchive.com/images/dehn5.jpg

I think it was meant to, but it's so subtle that it can't help but be ambiguous. I hold to the circle theory myself, but I think that Battle tries so hard to be positive after the dark Conquest that they found themselves in a corner were the only way to tell the audience that the future was in fact going to suck had to be so subtle that it wasn't clear.