The Sims: The Complete Collection Cheats

First, buy yourself two of the "Fancy Feet Dancer" cakes. This will NOT work unless you have more than one cake.

To See Jane The Dancing Gorilla:
For the first cake, hire the female dancer. Now, go to the second cake and try to hire another female dancer. The game will say that you have already hired a female dancer. Ignore the game and keep trying to hire one. After 5 or 6 times, a large pink gorilla named Jane will pop out of the cake and dance for you!

To See Sunny or El Viz
Now, I'm not sure how to get the character you want for this one, because as far as I can tell its completely random. Anyway, to see Sunny or El Viz, do the exact same thing you did to get Jane, only hire a male dancer. Again, after about 5 or 6 tries, eigher Sunny the dancing clown or El Viz, a boxer who looks a bit like Elvis will pop out of the cake.