Well, you are lucky.
Maria will be part of the next 0.20.0 update, Iwanka and Melonia will be part of 0.20.5 and Mrs. Smith and Annie have already won the poll for 0.22. Mrs. Johnson and Anna on the other hand will almost certainly be part of Erik's next update and Lopez and Martinez will be part of Judith's story (likely as alternative to her).
So all of those will almost certainly happen sooner than later.
Edit: The format was a mess.
Edit2: And here I am waiting for the Ms. Ross/Mia scene, which probably has a chance closer to zero, than to ever become relaity. :/