You shouldn't need the emblem as the requirement for it hasn't changed and it wasn't required to begin with.
I'm assuming that you have both gotten a 5 win streak on a Lighthouse passage and you have checked that it is that persons first time getting 5 win streak in trials since Edge of Fate launched?
With the above said, there is a hidden requirement - the person you're helping has to be in your own premade team (ie you invite them and then launch into Trials), they can't be a matchmade player.
Someone else will need to confirm, but as far as I know the triumph still works the same as before and you just need to have gotten a 5 win streak at least once in the current update on the Lighthouse Passage, and then once done you could help others regardless of your passage in future weekends.
What you may want to do is get a 5 win streak (but flawed) Lighthouse Passage and then continue playing on it, it won't convert to flawless and you would meet the black-and-white text description that shows on the triumph while you're helping get others their 5 win streaks.
Yea I had all those requirements.
I'm glad that I don't have to use an emblem. Sucks that I cant just team up with randoms and hope one of them goes flawless.
Thanks for your response.