Sorry for the late reply! Shop is closed over the holidays and im rarely at the (tool-)boxes 
Your problem was a mix of multiple things!
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with box2 you need a physx world operator in every event you want physx to be present, i just instanced the one from event01 over into the others.
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When using BirthStream you dont need position object/icon or speed operators since birth stream is a Birth, a position icon and a speed operator all in one with controllable settings within. So i got rid of your position object, speed by surface and physx drag since you can control ALL that in the birth group. I simply aligned the BirthStream icon to where your plane001 was, thats why it is a separate icon ;). That did speed up the overall flow as well as a welcome side effect

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When controlling particles with outside of box2 operators like find target etc. you need a physx switch to let the particles inherit an outside of the physx world influence. The switch with “speed” checked right under the find target does the trick in event02. Then all particles follow nicely but collide. I deleted the intercollision test as well as physx world takes care of that anyways. Same goes for the last event, physx switch under the lock bond makes them follow in the intended way.
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As a last cosmetic change i put the material operator in the root event so it is applied to all events in the flow. If your material is not animated or otherwise changing I would use a Material Static operator too.
cheers!
Ansi
few more questions, do you have any plan on making tutorials of what you do?