Hm. Maybe Stop as the second ability on Sephiroth, then. And the flowers are vulnerable to sleep, so I could swap out Sleep on Rydia for Lullaby on Tyro, give her an ST black magic, and just let the flowers snooze while I stop and mangle the pod.
EDIT: Boss rush report!
S/L'ed on the Dragon Pod until I got Stop to connect straight off, then used AOE to tear up the flowers before focusing down on the pod because Lullaby was clearly never going to get them all at once. It woke up at about half HP, and at that point I was able to use Blade Beam and Ruinga to keep the adds under control while taking the Pod down. Full medals.
S/L'ed twice on Atomos until an opening Lullaby connected, then used all my remaining offensive spell charges on him before he woke up. After that it was just a matter of attack attack attack SB attack attack attack. Of the members of my party only Sephiroth deals even okay damage with his basic physical so it was a long process, but Atomos only ate two people and I finished with 8/9 medals (lost one for actions).
Intermission! Used a mythril to full restore before the crystal fight, because if I can beat those two with no revives at all I might as well try to take out the crystals in one go (plus it's better for the damage medal).
Crystal time. No S/L here, it's all damage all the time against these guys. When you factor out the elements they null my AOE offense is 4 shots of Ruinga, two Blade Beams, two Darkmoons, one Valefor, and Cyclone Grimoire. Past that, I've got Waterga, Dark and physicals, unlikely to hack it against four bosses with solid offense. Would that be enough? *drumroll* Yes, yes it was! They died after three rounds of all-out offense, culminating in a Cyclone Grimoire. 8/9 medals, losing one for damage. Now the Antlion is all that stands between me and a second MC2. Nice.