Does a species appearing automatically unlock the special bitizen (?) in TDS?

I too have had the same experience with having the character, but not getting the occurrence of the scene.

I believe that the scene occurring is a random event based on if you have the characters.

If not, then it is one of the large number of bugs that are in the game. The developer has said they are working on them, but until then, this may be the cause of one of them.

I have had the toydarian unlocked in my album and available in the store for 1 bux, yet seen many appear as ? While still available at the store.

When used from the store for 1 bux, he came and was delivered to a floor and checked back in the store and no more toydarian for sale, maybe the store is one use way to get a ? character?