Mastered both of the new holy/dark magicites, holy in 27 sec, dark in 39 sec. The Holy magicite felt like the easiest of all 8 dungeons, but that Dark magicite dragon, he's rough!
For holy, my initially planned team worked out perfectly with a small change. Instead of being an entrust battery, I had Onion bring Boost (used on Shadow to ATK cap him), and Drainga (for some minor added damage). Because my dps was high enough I only ever saw one mist phase at the very end of the fight, and after farming some +dark magicites, I can easily farm it with probably no mist phases at all.
For the Shadow Dragon, I had to adjust the team some. I have zero chance to dps him hard enough to skip the black fang auto-kill, so I had to team tweak to work around it, benching Yshtola for Yuna (USB). My solution was to give Faris an auto-sentinel RM so that she ate the initial attacks guaranteed, and I held off on using any heals in the beginning so that Faris was 100% the lowest health on turn 4 and she ate the black fang. I had it timed so that as soon as black fang went off and killed Faris, Yuna's USB landed, raising her, giving her a new haste, and putting last stand on everyone and then the first cast of wall landed, including the raised Faris in the buff.
From there, it was just a matter of entrusting a bunch of soulgauge to Firion so he could combo USB -> OSB for lots of dps with Raines doing his usual crazy damage. I struggled on the kill, because my non-dived Yuna had serious issues trying to solo heal the fight, so for repeat kills I'm going to make Onion a backup healer (on my kill I had him casting Diaga for absolutely worthless damage, so that's an easy swap).
Now that I've mastered all 8 magicite I unlocked the 2nd magicite roaming warrior, but I don't know that I'll use it over the wall RW on any fights. Anyhow, here's the video of my first clears on holy/dark if interested:
Mist Dragon 27sec ---
Shadow Dragon 39sec