See Party Missions for general overview of party missions. This mission works in the same way as the normal Rafflesia mission,
except there are also 3-5 Sabre Tigers (L115 Life) roaming around. So just
use the same tactics. Kill the mobs (L108 Life) for Rafflesia Petal which can buff
up to 3 families. Use scout as leader to get the buff so the attacking characters can continue to deal damage.
If you have problems managing the mobs , assign families to kill only mobs for the DPS families. Scouts should stay out of the boss' areas of effect. The Torso (and some mobs) can only be hit by ranged characters, so avoid bringing melee characters.
Like normal Rafflesia, the boss has 2 skills - one knocks characters outwards, and one pulls them inwards. Run out of skill area if possible, so you won't get drawn in and die beneath Queen Eater, making resuscitation problematic. Kill Queen Eater Legs first, followed by Torso (considered flying), and then finally Egg.
Rafflesia can inflict [Confusion] status which disables skill usage. This can be removed with Refresh Mind from [Tactical Assistance] stance. Likewise, [Poison] status can be removed with Recover from [Medic] stance.
Since this party mission is similar to the field raid version, see Wiki of the New World: Raids for more recommendations or tactics. See also クエスト/ラフレシア 党.