Oliver/Marlene
Marlene was making a point to talk to EVERYONE, and she meant that literally. No one was going to be alone or bored or both if she could help it. Besides, she had always seen the Order as a family and there were too many members whom she didn't know.
When she saw Oliver, she walked to him and hooked her arm with his. "Hello, love, and yes, this is a lot more impressive. You get me, Dumbledore and Grindelwald planning, and this is what you get."