1.) You might notice some distortion in the air from the Ikiteha, but it's not like dragon ball Z where it's all glowy and stuff.

2.) The parts where they come in contact would cancel each other out, so effectively it would get smaller the more rockets it hits. The blade is about 8 feet long, so it would have to hit quite a few to be neutralized. My reasoning is that it's a single dense attack vs a dispersed scatter-shot and that the Ikiteha is designed specifically for cutting through things, so I feel that parts of it advancing through the volley is reasonable.