Here's that snippet about Julian possibly coming back to Charmed (from a French magazine):
3rd question: Charmed may stop next spring. Are you ready to return in an ultimate episode ?
A: Of course. I promised to Alyssa Milano to take back my role of Cole Turner, if the 3 girls wish so, but I'm waiting to be confirmed with the end of Charmed. Producers have decided nothing yet. I was part of the 150th episode to show my fidelity toward this team who helped me get spotted.