CHARACTER LOGS
Lily sat attentive for most of the meeting, leaning slightly forward in her chair and idly playing with her wedding ring. When the Marauders were all assigned a task, she frowned slightly but covered it almost at once; of course her natural impulse would be to want to go along, but there was Harry to think of, and besides, those four knew the castle better than anyone else. She took James' hand and gave it a gentle squeeze when Dumbledore explained the assignment, simultaneously communicating "congratulations" and "be careful, numpty".
When Regulus was introduced, Lily sat up straighter and narrowed her eyes, then looked immediately to Sirius. She understands what it's like to have an estranged sibling, though obviously this is a far more grave situation, and she is less than pleased that Dumbledore didn't at least warn Sirius, if no one else. Of course, though, she trusts Dumbledore in regards to Regulus' presence in the Order, and assumes he must have some reason for including him.
At the end of the meeting, Lily follows James and the Marauders to discuss the evening's events with them.