Character mistake: Pete says that Terry Bradshaw's corvette is a '75 stingray. It is actually a 1981 or 1982. 1975 corvettes had a rear window that was perpendicular to the ground. 1978 and newer had a sloping rear window.
Continuity mistake: Kyle Reynolds just said that he wishes his dad were still alive to see mom's wedding. His nephew Ethan goes "Yo, Uncle Kyle." In the exchange, Kaylani's hand moves from Owen Wilson's shoulder, to his arm, to the shoulder again. (00:05:20)
Continuity mistake: In the first scene with Kaylani, she puts her hands on Peter's face (her hand also disappears from his shoulder briskly during a cut, incidentally). Between shots you can easily spot how her fingers are placed differently each time, in particular the index finger is on or behind the ear. (00:04:40)