As far as the particle stuff goes, you probably have to get into the new Stardust plug-in which allows more control via its nodal flow graph and including conditional triggers. Same for any 3D program's particles like Thinking Particles and X-Particles in Cinema 4D, PFlow in MAX, Houdini's particles and so on. Some things simply can't be done in a simple manner, least of all in AE. the expression stuff can easily be modified by including the "value" function and tying the parametric definitions to a slider with a multiplier to modulate their intensities.
the expression stuff can easily be modified by including the "value" function
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