Sadly, statistically, and just gut feeling, they're both dead and have been since the night Riddle was murdered. IMO obviously, but let's be logical and realistic. With what they saw, were part of and likely said in moments of great fear all lead to them having been killed to keep them from talking.
Would love to know of some cases where two women go missing, after being part of a murder, and one has children... And they aren't dead.
Life isn't like movies in situations like this.
They aren't on the run, laying low and living off some money they had saved up, avoiding all social media and cameras waiting this all out.
That just doesn't happen.
I will be happily shocked to be proven wrong, but I think they were killed within hours of Riddle.
IMO.