Outtakes were only added halfway through the theatrical run of some of the films you mentioned as a ploy to get people to see the films again. There actually is a variation of outtakes during the final credit sequence in Nemo. Unfortunately, most people leave the theatre so they don't see them. Outtakes are cute but it's the film that is the main attraction. (I'm sure the DVD will be full of extra stuff).
Nemo is poised to pass The Lion King this weekend in its regular theatrical run. It has also never been lower then #6 at the B.O. since its release. Yesterday it climbed back up to #4. Nemo will probably need an IMAX run to catch the total theatrical box office dollars of Lion however.
Congratulations to the little fish that could. Finding Nemo has surpassed The Lion King's theatrical gross of $312,,855,561. Adjusted weekend figures put Finding Nemo at $313,119,898. Next target is the $15,686,215 million The Lion King made at IMAX showings. Looks like Nemo will reach that before it goes into IMAX theatres!