Riley: Flowers and a note saying he knows what a shitty gift it is but he can't think of anything better and that it's basically an IOU a better gift.
Herc: A pair of briefs with 'Foxy Grandpa' on the butt.
Cronus: A prank wind-up box that promises something sexy but when you crank the handle a fist comes out and punches you in the face.
Dualscar, Herc and Riley will all find a single white rose somewhere in their rooms. They probably won't know who it's from or what it even means, but it's symbolic. It means you've pissed him off and he's watching you.
Septimus unfortunately isn't getting anyone anything for Christmas because he has nothing of value to offer anyone. Also he doesn't have very many friends and doesn't feel the need to buy anything for anyone.
Dirk: A note saying his new years resolution is to TRY and be a little more tolerant of Dirk's troll friends. Also a (sloppily, but he tried) bound comic book featuring Sweet Bro and Hella Jeff in never before seen scenarios. This shit is off the chain, yo.
Roxy: Something similar to Dirk's present, but this one features Sweet Bro and Hella Jeff as wizards.
Dante: A glass of tomato juice. Probably not as good as a V8 but he made it with love and irony.
Damara: He isn't sure if Damara celebrates Christmas but she will receive an assortment of chocolate, all made with the chocolate charm he has. He'll also come visit her on Christmas day and bring coffee from the coffee shop and spend time with her for Christmas, if she isn't busy.
Regulus, Remus and Sirius: They all get chocolate, too. He's also compiled notes on how magyk from his world works, what the Wizard Tower is like and things of that nature that he thinks they might find interesting. For Regulus, he adds a few extra pages on Witches and how they differ from Wizards, including facts about the Wendron Witches.
Roxy: She also gets chocolate! Because he has a chocolate charm and he's putting it to good use. But she also gets another charm, one that will call her cats to her if she ever finds one of them missing. It might also have the added side-effect of attracting other strays by accident. It's written on a little stuffed mouse, which he thought would be a cute idea.
Dolorosa: She gets chocolate and a thank-you note for helping him and being so friendly.
Marco: He gets a charm that allows him to go invisible for a short period of time when he uses it. A half hour, at most, depending on how hard he's concentrating when he uses it. It's written on a piece of transparent paper, and there will be a note explaining how to use it and to make sure he keeps it safe. If it tears, the magyk will start acting funny.
So basically if you have CR with him you're getting chocolate.