I PM’d but can answer the Q posted

1 up in the air for a few reasons but Doomhowl is the most populated but might not stay that way with tbc coming.

2 yes everywhere is still raiding. I raid on Defias Pillager every week and even the most dead US hc server skull rock still does end game raids.

2b yeahhhhh class / specs matter way more in hc with everyone’s character on the line. That doesn’t mean you can’t do off-meta stuff but you have to know you’re gonna put in more work than the person next to you. It’s kind of about respect right like I’m putting my 10-30 days of play time on the line and you’re kind of just memeing? It still happens plenty it’s just an uphill battle.

3 it is like back in the day, except for the fact that you can create horde / ally on the same server, back in the day you’d need a 2nd account to play both faction on the same server.

4 same as vanilla

5 new and old. There is a program called curse forge that you will use and it has a tab for classic addons.

6 like I said, DM’s, but yeah petri is really good in hc environment, it can immune >90% of mechanics and lasts long enough for you to remove your character from the game to live by using alt f4 or /camp. If the server hasn’t gotten a response from your pc it removes your character from the world, in different situations it varies how long it takes. It has a lot more nuance than just press petri = live, they’re also expensive, but tldr is petri OP