Memphis definitely did - I saw her myself a few years ago in NYC.  She took a break about two years ago when she had her baby.  Whether or not she decides to return again is anyone's guess.  Last I heard she is very happy being a mom... and I don't think she's filmed in the last few years either.

As for Ava, for an answer from the source: read the linked page.  

Caveat: she would not be the first to provide but to deny it publicly.  However, I have seen nothing to indicate that she ever provided.