Nostalrius Begins - Quality wow vanilla realm (1.12)

The legal system is often too complicated, and since noone will answer more delicate questions (for free) it is often arguable what is actually legal. Hence I'm curious about the following, if someone with some insight could answer:
Is it illegal (i.e. which could lead to a fine/sentence in court, not just to break a EULA and be banned from e.g. Blizzard account) to:

1. Play on a private server with a downloaded WoW client. With or without your own copy of the client. This is what all the users are doing.
2. Participate in coding the core of a private server, although you are not the one to host it/make it available for general use.
3. Not only coding, but also making available the core of a private server, such as cores hosted on GitHub or other public code repositories.
4. Host a private server. (I.e. is a hosting company doing something illegal when it is hosting a server).
5. Facilitating the project running a private server (but not actually be the name of the hosting contract). This would be people like admins/GMs/forum/site contributors.
6. Hosting a web site with Wow (Vanilla) database, talent calculators or similar tools that contain names/art/icons from the game.

Cheers.
PS. Bored out of my mind, waiting for the next big thing.

You say "not just to break the EULA and be banned" as if they are going to cross-reference any hypothetical shenanigans with being a legitimate subscriber. They will never ban your account for those reasons, because they are making money off of you.
As to your questions, unless you are interfering with their ability to sell the retail game by publishing a service which would distract players away from the retail game (which is why Nost went down) then you don't have anything to worry about.
Coding some private server isn't the problem, however the act of publishing the server online to players will potentially hurt their business and might lead to the server going down. If you create code and post it to Github, I as long as it's your code you are publishing then there wouldn't be a problem.
If you host a web site, then you might be contacted if there are copyright violations and asked to take them down.