1) There wasn't because I as a person never remember to use tags BUT I WILL SET THEM UP TOMORROW, so character tags will exist for people to use but it'll be on them to tag posts themselves if they want to track their threads that way, versus a having a separate thread tracker in their journal.

2) Currently all the areas blocked off are inaccessible and can't be broken into even with a lock pick or superhuman hulk strength, mostly because it's game start and this will change in the future. That said, Komaeda has been going around the ceiling/crawlspace between floors and Kokichi or anybody else can absolutely also be there and go "hm" at each other!