Nope, it is only air escaping from the top - if it wouldn't, then the pressure inside the spheres would grow from the heated air and prevent Kzich from vaporizing at all. And since it is pretty dense, Kzich vapor would collect on the bottom instead of escaping with the air. 

As for the spheres, precisely yes. Not all of the spheres, but since Ido used them to chase Sol into cover, most would be floating in front of the tree when he launches them.