I was curious as to why the MiiVerse 3DS screens released lacked the messages icon present in the Wii U version so I contacted Nintendo for clarification only to be met with some bad news. The 3DS version of MiiVerse will not support message exchanges between friends or the friend request feature. It's just the community features. And just like that the 3DS is back to lacking a means of contacting friends.
*Not really sure if this was already known but thought it would be a good clarification.