I haven't confirmed yet, but do participating in Crimson elites/bosses will grant progress on this medal ?

I noticed that when you make a progress on medals you will see the medal at the top of the medal list (unawarded medals), but when someone disabled my korteth, I don't see the medal on the top - not sure if the progress is added or not - I'm just making sure

not entirely sure about this ... but my belief is that only the last person who hits a crimson boss will get credit for the medal (if they are working on it).

Yes they count towards the medal if you are the one to disable them that is why I try to get on to any Sha'din or Crimson elite that is alerted by the legion and be the one to disable it as it works for both medals.

The person who gets credit for the kill is the last person to hit it before it gets disabled. So yes.

so not all 4 get the credits ? Too bad then Anyway question answered, thanks guys