Didn't go through the thread, but you need an entertainer's visa to perform in Japan. I use to bring over Djs from the UK & US and sometimes we had to do some wacky shit to avoid them being caught. The visa at the time costed about $3,000. A lot of money and not realistic when you expect to net that much for the show.
Don't know how big these guys are, but due to past experience you would think they would be legit this time.