I have been a long time user of the app, so I can jump in with some answers.
If you have these members already separated in groups somehow, then your life will be substantially easier. You can tailor newsletters to only send to specific groups. This also answers your point about Banned members. Just make sure your newsletter doesn't point to them.
Yes, easily, and if you have multiple calendars, you can do a seperate newsletter for each.
Yes, you can base it on number of views and number of replies, cut off for how old it is.
I don't have downloads, but it works in Commerce.
You can do any manually added content you like.
It is under manage profile - Newsletters.
You would need to setup a new Newsletter to default to no-one and then people would need to opt-in manually. I don't see anywhere in the app that recognizes that field in IPS. Headstand can correct me obviously.
See above, probably not.
You would probably need an app to move users into a group after their account has been stale for more than a year and then cut that group out of all distro lists. I use https://invisioncommunity.com/clients/purchases/58978-inactive-members/ and it works well.
As the Opt-in during registration does not seem to integrate with this app, I would say this isn't possible. They would need to opt-in to each newsletter. Again, if I'm wrong Headstand will correct me. It would be a nice feature that the main Opt-In for bulk emails automatically subscribes the user to the default newsletters for their group membership.
Hope this helps.