The Lion King
Though they talk like humans, the characters in this movie are still lions, and some light googling on basic lion behaviors will tell you that your average pride is made up of one or two males and a bunch of sister-wives. Think about it: Though Pride Rock is teeming with a bunch of fine lionesses, how many adult males do you see in the beginning of the movie? There are two, Mufasa and Scar, and since, like all Disney Villians, Scar is clearly gay, Mufasa appears to be the only available inseminator around. The evidence would suggest that Simba wasn't the only orphan he left behind, which is upsetting if only because it makes that whole Simba/ Nala relationship 1 million times more incestuous.
Let's be honest. There's absolutely no chance that those fatties are getting out of their chairs to pull back their sagging guts and get it on. How the hell are they reproducing? It's impossible to say for sure, but given the rest of the movie, the most logical explanation involves some robotic hand jobs, and a series of very dirty pneumatic tubes.
The movie just says that Rapunzel's hair is imbued with magical healing abilities, it doesn't specify which hair. My guess is she has quite the situation going on down there.
Much of the movie is spent establishing that the toys have been in Andy's room the whole time he's going through his adolescence, which means that they're certainly there when he's doing what adolescent boys go into their room to do. It's definitely happening, and given Andy's willingness to take a stuffed cowboy to college with him, and his gross CGI shovel face, my hunch is it's happening a lot. How do Woody and the gang handle this? I mean, I'm assuming they don't watch him or anything, but they must be aware what's going on, and anyone whose ever had a college roommate can tell you, that is a super awkward situation to be in day in and day out. At the very least, it makes it hard to believe that the toys would still be so eager for Andy to play with them, knowing where his hands have been.
The Little Mermaid
Given that she was fish on the bottom for most of her life, it stands to reason that Ariel did like fishes do and nonchalantly went to the bathroom where she swam. That coupled with her general misunderstanding of all things surface world, is enough to suggest that there is an unseen moment in the course of the film when Ariel washes her hands in a toilet bowl and then poops herself.