Funny Stuff from Final fantasy about the characters
The phone Vincent carries in Dirge of Cerberus is a reference to a couple of points of comedy relief in Advent Children, in which Marlene requests from both Cloud and Vincent a phone to call Tifa and Cloud tells the phone-less Vincent that he'll give him a call, with Vincent later asking Tifa where he can find a phone shop when entering the battle with Bahamut SIN.
In the Reminiscence of Final Fantasy VII featurette, he speaks on the phone with Cloud, telling him to pass a message on to Yuffie; "This is my phone, and she has no right to call it".
Near the end of the game's Disc 1, it is possible for the player to set main character Cloud Strife up on a date with her, Aerith Gainsborough, Tifa Lockhart or Barret Wallace. During the date with Yuffie, she will kiss Cloud, leading to an awkward moment between the two which ends with the sound of Yuffie smacking Cloud.