If you're interested in learning more about them, I would suggest you talk to Luke Skywalker. He probably knows the most about the Order.

[Leia might be training, but she knows only what she could get from her father's secret papers. Vader and Palpatine destroyed nearly everything they could get their hands upon after they came into power.]

Yes, I'm sure that if any one of here suddenly came up missing in our timelines, then our realities would face voids that could destroy things altogether. Especially when such large groups becoming missing from the same world.

[The Force moves in mysterious ways. Or something like that.]