With wow macro's a lot of this is easy to accomplish.
However you're then clicking with the keyboard.
I suppose you could use something like Domino's to place a bar somewhere, with only a button or two on it.
Which would then be clickable wherever you wanted.
Not sure if you can cancel a buff, by clicking on an action bar. Clique has actions based on unit frame clicks.
But putting a macro to cancel a specific aura on a button works too.

For example
#show Ice Block
/cancelaura Ice Block

I'm pretty sure that's the syntax for /cancel aura.
The problem with mouse clicking on the buff itself, buffs aren't always in the same position on every toon.
But you could have a button (UI Element) positioned the same for each toon.
And go with a repeater region quite easily.

I usually have self buffs on Shift D for each toon.
In a mixed group it might be...
/castsequence reset=5 Inner Fire, Null
/castsequence reset=5 Fel Armor, Null
/castsequence reset=5 Water Shield, Flametongue Weapon, Null

An addon like Smart Buff.
With a repeater region going to each client from every client over the button would work too.