As far as I know the slack is not closed. I'm still in the slack and can see other people conversing there as well. It has been infected with phishing messages lately, but a lot of slack channels are now.

As for your second point; I was one of the people whose coins 'disappeared' in the swap a couple of months ago (you can see my older messages in this thread as proof). They actually did not disappear, but were stuck on the old network. The team set up a verification system for this and after sending in a ticket and following instructions, I received my balance back in a new account on the new network.

I can't speak on the dev leaving. I haven't heard/seen of that. But in my opinion, people are allowed to change jobs whenever they like. Doesn't mean anything on the face of it.

I'm not saying everything is all cool with the project/coin, because I don't have in-depth knowledge about what's going on inside the team. But I do have answers to 2/3 of your questions that might help you put some things in perspective