Mrs. Ari's first name (Melissa) is used by Dr. Marcus (Nora Dunn) when in session with the two Gold's. It's also used when Lloyd talks to her near the end. Her first name was never used prior to season 8.
The epilogue, although ambiguous, is meant to show that Ari will always be Ari - it's in his DNA.
The track from Sara Gold's CD playing in Ari's office is Nuestro Amor Es Más Que Grande (Our Love Is More Than Great) by IL VOLO.
This is the last episode of the series.
Alan Dale and Melinda Clarke worked together on The O.C.