[Vague spoilers on Music Note, Three Spears and Sun Class play-style warning]

I'm not sure how much this will help, but we did this scenario on our first attempt last night as we happened to have the right cheese. Item #133 Resonant Crystal which you can get from Scenario #84.

Our Music Note supported by our Three Spears was able to zip about the map using various items that allowed extra movement and jump and used item #133 to pop each tree. Meanwhile our Three Spears was able to stun both Oozes whilst the Sun class was on tank and damage dealing duty. Only one tree managed to squirt out an Ooze thanks to this cheese, and we got lucky with the Imps shielding and healing rather than multi target curse attacking all of us after we were poisoned.

Someone is probably going to ruin our day and say we can't use item 133 to destroy the trees however!