Is Hollyleaf in Starclan

Yes, in the book The Forgotten Warrior (Omen of the Stars) she returns to ThunderClan after living underground and hunting on the other side of the hills. She returns after helping Ivypool and Dovewing out of the tunnels, and confesses to the clan that she killed Ashfur. She is welcomed into the clan, but rejected by some of her old clan mates for some time. But she also helps the clan train in fighting in tunnels. You can read the story of her in the tunnels in the newly released book, "Hollyleaf's Story"