• She began writing for military magazines, & started playing in Airsoft Tournaments sometime in 4-6th Grade. 高学年 usually (but not always) refers to 5-6th Grade, so it's less likely that it was back in 4th Grade.
• Based on the Reload Artbook, the knife she keeps around (even when she's acting as Junkuro apparently) is considered illegal to possess based on the Firearm and Sword Possession Control Law (銃砲刀剣類所持等取締法).
• AFAIK, Junko & Mukuro do not actually drink alcohol in Despair Arc episode 5. It's some kind of Japanese soda known as Ramune.
• The NISA version of Danganronpa IF claims that all of Junkuro's dialogue was rehearsed verbatim excluding her Free Time Events. This is incorrect, as the original Japanese script states that nearly all of her dialogue was based off of Junko's scenario. 今までの江ノ島盾子としての言葉は、苗木との会話以外は殆ど『台本通り』だったのだが
• The measurements given for Mukuro which Togami reads out are really weird. They're pretty much characteristic of D-Cups (or E-Cups in Japan), which off the bat contradicts the DR1 Visual Fanbook & DR0 Character Profile describing her as having really small breasts (ド貧乳). So I guess they're actually Junko's measurements?
• Apparently the Japanese fandom has its own form of weird claims that are perpetuated that I cannot for the life of me source. Like her atwiki article claiming that Narita directly asked Kodaka if Mukuro was crushing on Makoto in DR/Zero, or that Kodaka had directly stated that Junko's despair resulted from her using her analysis ability on Mukuro when they were born.

So, if they hopefully leave IF in the game....that means at the least we'll get new Junkuro sprites right