Not entirely true. I think some of those criteria are correct, but not all. For example, I know for a fact it doesn't have to be the same avatar. I teamed up once for trials 1707 & 2194 (pet kills in ice day/weather). These are on the Pet:MAB staff path. I was using Garuda, and teamed up with a SMN who was using Fenrir. The only time one of us wouldn't get credit is if we had no avatar at all. Different avatars are ok, but you have to have a pet and the target has to have been killed by a pet. Which pet or who's pet doesn't seem to matter. (Note that this obviously isn't the case if the trial specifies killing with a specific avatar... then everyone really does have to be using the same one. If it's just any pet kill, it doesn't matter.)
Also, I'm fairly certain you don't have to be on the same trial, as long as the conditions are met. I'm less certain on this one, because the person I teamed up with was JP. I was on trial 810 (150 undead kills with 50+ wind damage). He was also on a similar trial (required wind damage kills or pet kills, not sure exactly what) but he required skeletons specifically, not just any old undead. That's how I know he was on a different trial than me, but we still both got credit.
Also adding to this, I did my finishing blow 50+ light damage for cure staff with a beastmaster finishing enemies with primal rend, which is light damage. I used carbuncle (on smn) / banish (on whm) when doing the trial prior to him helping me. My friend, the BST, was not doing a trial. His primal rends counted toward my trial.
Essentially, whether they are doing a trial, or doing a different trial, all that matters for your trial is your requirement.
If you have pet kill, it doesn't matter if it's an avatar, fellowship npc, wyvern, jug pet, automaton, or charmed pet. It just has to be a pet kill, by you or someone in your party, on whatever mob is required.
If you have specific avatar finishing blow, it doesn't matter whether it's your avatar or someone else's, but it has to be that specific avatar
. Like if a summoner doing no trial is helping you do garuda sheep finishing blow, they must be using garuda for the kill for you to get credit.
If you are with a summoner doing a pet kill mab staff, and you are doing a specific avatar, have your friend use the avatar that is specified so you both get credit.
If you are doing separate avatar trials (ie garuda sheep vs shiva sheep) then you cannot do it together
. Either one (shiva OR garuda kill) gets the credit, or none (ie your melee hit building tp for spirit taker kills the mob).
Essentially... the requirements for finishing blow trials now extend to the entire party, but they must use the specified method that you must follow. Edited, Nov 7th 2010 4:25pm by Annalise