P.S: this will not be a place for asking for help with problems to do with your game or the engine; that's what the forum is for!
sure, why not...I believe you can create widgets for it, but a link on footer of this website should probably suffice. Could also mention it on the wiki & provide a link on the Steam group.if this discord server will be "official" it would benefit if it gets mentioned on some further sites here beside the forum(wiki, special page/navigation bar? , maybe add this widget somewhere, facebook/twitter post)
I'm inez mate. Slack kind of sounds like (based on what I just glanced on the website) something like Asana or the new thing Thomas (Marvel) has created for planning & discussing projects. Discord is more of an IRC & alternative to Teamspeak/Skype due to low system requirements & bandwidth usage. Personally I use it to chat on EA server & for voip when I play multiplayer games with a couple of people from here - specifically Battlefield & Overwatch.
The guy doing Asylum/Dagon engine uses a slightly different one.. the name eludes me right now.. Slack maybe