For Hermione: Earmuffs and a classic book of wizarding literature he doesn't think she's read.
For Bill and Fleur: Gift vouchers for a meal with wine for two at wizarding Italian restaurant and a promise to babysit when they decide to go.
For Victoire and Dominique: Set of dragon bookends and some animal-themed dressing up clothes he thinks they might like (with receipts).
For George: A slightly mysterious note which will clue him in to a possible supplier Charlie has contacts for and an assortment of vouchers for a weekly takeaway, enough for two months.