How do we communicate across these channels?

Some of these threads are getting flooded with much more text than may be necessary.

Agreed. One part of this I think is agreeing on the notification protocol for Slack. Proposal incoming.
The other part is having an understanding of what each of the tools are for. In the end it became clear due to the way the Trello integration works. Long story short, consider Slack an "event hub", where all information regarding the community comes in a chronological feed. Use it as a springboard to jump in to the other apps, especially Trello, because often the data only goes one way; and in this case, replying to a Trello notification on Slack does not push the message into the Trello thread.
So these two things are kinda intertwined, because if we agree that you don't need to enable notifications for all messages - only "@ mentions" - then the spam in those channels becomes less of an issue because they won't bring up notifications in your phone all the time and they'll still show you what you haven't caught up with next time you decide to come in to check.

Oh, and in that arrangement we basically all agree that if you need someone's attention you have to tag them, or tag @everyone to expect a timely answer

What details do we need to communicate for resolutions and outcomes?

If necessary to resolve conflict within context of the thread, what are appropriate ways of communicating our emotions?

I'd like to hear input from others in the group before I jump in on this (:

My recommendation is to adhere to the constitution guidelines on communication along with practicing NVC methods.

Can the above items take on a succinct format that reduces the length/wordiness of our posts?

Is this a detail issue, or an overwhelm issue? Like if we implement a framework for working groups and you only need to keep up with a subset of what's going on in Loomio, does the length of some of the more complex posts become less of a problem?

@pospi its a detail issue. Succinct formats to transfer information offer better time efficiency. Ideally none of us would occupy each others time more than is absolutely needed. I wouldn't read a lengthy rambling from a journalists, especially if their major points were not summarised first. If someone is unable to keep it short I propose subtitles to allow the reader to hop through lengthy posts.

Can we all agree that our communications will be focused on moving forward with solutions instead of "he said/she said, should have/could have discussions keeping us in the past"?

This is absolutely my intention and I wonder if this could be an expanded-upon item in our constitution?

Good point succinctly made