Theo and Andromeda
Unlike many, Theo did not avoid anyone at his party making sure to talk to people and keeping them happy. He might not like them, and would have preferred to never speak to them, but there was no excuse for being a bad host - especially not when the guests could kill you if they felt insulted.
However, there were people he'd rather speak to than not, and so when he walked up to Andromeda it was with a bit more genuine smile. She wasn't Belvina, and he might wish that this union would never happen, but it was vital that she felt at home so that her loyalty stayed with them, rather than with Bellatrix.
"Andromeda," he said easily, refusing to call her Miss Black when she was to be married to his son. "You look lovely this evening," he said, taking and kissing her hand. "Would you mind sparing a moment for your future father in law?" he asked. "I would like to get to know you better."