Regarding your answer about Gettysburg Day 1 not being a Meeting Engagement: it certainly looks like one the way both sides funneled newly arriving units into the fight over the course of the day. It's certainly a contrast to Antietam, Stones River, and other classic battles where both sides are mostly or completely deployed prior to fighting. However, you make a reasonable argument why Gettysburg is not a Meeting Engagement.
Would you consider Chickamauga Day 2 to be a Meeting Engagement? Due to the actions of Minty and Wilder on Day 1 it seems both sides were at least somewhat aware the other was in the area. However, both sides were feeding in brigades and divisions piecemeal throughout the day as they arrived on the scene and those units kept stumbling into each other in the thick terrain.