I need confirmation on this..

Say I am in a legion and I alerted a boss but I leave for another legion before it's killed
Would...
A) I be able to alert it again?
B) The people in the first legion still get rewarded if I kill it in another legion?

You can not realert.
People will receive the rewards if you kill it.
If you return to legion you alerted it to, they can view the elite from the link in their news log. It no longer shows up in battle tab view elite/bosses button.

Thanks

Slight correction needed - Other people will *only* receive rewards if you kill it before the 'memory' of their damage on the log gets wiped.

Happened to someone I know with one of the alertable Planet Blockage NPCs - because they were low level it took them quite a while to finish killing it on their own and the Log of damage got wiped.

We are talking about elites you can alert, not single person NPCs that don't expire.

I think they were talking about the TO Hyperseeker.

Interesting, that probably would only apply to Hyperseekers then. All other Elites/Bosses have timers that would probably prevent that situation.

How long did it take him to kill the Hyperseeker, approximately? Are we talking days, weeks, more?

Huh. I've never had a hyper seeker.
I assumed they had a timer.
My bad

Not sure exactly - but certainly at least a week or two because she went on holiday and started hitting it again when she came back.

Yeah, no other alertable NPC can stick around for that long, so it would only be an issue for the HyperSeeker.