Mako is the the only character to have noticeable freckles.
Chapters: 69, (Breifly) 99
Yuri and Mako eat lunch very often so it's likely that they are close friends, however that is not to say that they do not have their differences. They were having a fight before the school trip to Kyoto, which ultimately caused Yuri to be in Tomoko's group. They have since made up and continue their friendship, which has extended to include Tomoko in their daily lunches and even group texts (chapter 99).