Akagi/Headscratchers

Names

 * Akagi and Washizu are both introduced as Akagi Shigeru and Washizu Iwao, respectively, rather than Shigeru Akagi and Iwao Washizu. Why is this? Did the Japanese have a lapse in their naming conventions following WW 2?
 * The naming is in the usual last name, first name order the Japanese have always used. Shigeru and Iwao are first names, Akagi and Washizu are last names. So Akagi Shigeru and Washizu Iwao is the correct order.

Kawada Group

 * At the start of the Fake Akagi arc, the boss of the Kawada group says Ishikawa is the only one in the group who has seen the real Akagi before. But didn't Akagi meet other members of the Kawada group (Ryuuzaki, Yagi, Kurosaki) six years ago? Did they all die or leave the group in only 6 years?