Returning player a bit lost about professions (WvW)

I'm returning after 4 years and I'm completely lost about professions (except that scourges and firebrand are the meta) so I would like to ask you some quick questions so I can get a general view of current classes.

1- Which professions are viable (not top dps) for AoE?

2- Which professions are the tankiest in zergs?

3- Which professions can dive in and out from an enemy zerg without killing themselves?

4- Is sniping people from enemy zergs viable? And which professions are able to do that?

5- Is there a profession/build that is viable for both roaming and zerging? Obviously not something OP but just viable.

6- Is there any bow build from any profession that is viable in zergs? And rifle? The last time I played the only one was shortbow thief just because of choking gas spam.

7- Which professions are currently considered "piano classes"? Like elementalist. And which one are more straightforward?

8- How updated are metabattle's builds? And how viable are the "great" and "good" ones for WvW? Because reading the comments there I can only see things like "do no damage (from a ranged build)" or "too squishy (from a zerging melee build)" and those builds are tagged as "great" or "good".

9- Which professions/builds are good for CC in zergs?

Thank you in advance!

1. Ele, necro, rev. They are viable because they are top. Special mention for thief who can also provide strong aoe spikes with staff, but requires stronger melee force and/or clueless enemies.
2. Necro, mesmer, guard, warrior. Rev and thief are very good at avoiding damage for some time, but I wouldn't call them tanky.
3. Mesmer, thief, warr, guard.
4. It is viable, but it's generally more useful to snipe multiple people at once (like with revs). Mesmers, thieves and rangers (esp rangers) are quite strong for single target ranged burst. Warr is also becoming popular slowly with its oneshot rifle build.
5. All professions except ele, ranger and necro have strong builds in both. Ele and necro arent that amazing for roaming (same with ranger and zerg). That doesn't mean that they arent viable, but you'll be more useful on something else.

   Builds that play relatively the same in zergs and roaming would be spellbreaker, herald and scourge.

6. No, those are mostly used for sniping or roaming.
7. None. It just takes some time to get used to certain classes/elite specs. Even ele has like 5 useful weapon skills, so the only piano part is knowing how to get to them as fast as possible. I'd call anything except guard (and maybe ele/engi at start) strsight forward simply because that your mistakes dont affect others that much, so you have quite some time to get used to the class (which isnt even that complex compared to mentioned 3).
8. It all depends on server (or even region). Join voice chat and see what commanders usually ask for, join discord and ask what's generally needed. Generally they should be playable, but there's no reason to have healing tempest/herald for example when you can just bring scrapper.
9. Mesmer, ele, necro (mostly through corrupting stability). Warr is decent when it gets in melee range.