Random bit of wordplay that wasn't brought up in any of the TL notes: Japanese number puns! The numbers from 0 to 10 have relatively simple pronunciations, so they're often used as pseudo-kana in order to spell out words. For example, 4649 is read as yoroshiku (yon-roku-shi-ku -> yo-ro-shi-ku)
The cheerleader uniform in Iiko's fantasy has the numbers 115 across the chest, which spell out her name (ichi-ichi-go -> i-i-ko).