You can mouse broadcast with Keyclone, but its not a strength of the program.
To do it with keyclone, you'll want all of your mouse target AoE's on the same hotkey.

You will press the hotkey for your AoE stuff.
Then press a user defined key, which enables mouse broadcasting.
Then target the AoE with the mouse on the main screen.
And click the ground.
Which will have you PiP swip to each window in succession, and replicate the click in the same position on each screen.

You can configure your key here:
Keyclone >> Set Up >> General Tab >> and set a "Pass Mouse Click Hotkey".

Unfortunately KC's PiP swap speed is not the best, so it will take a while to get all of the spells off.
It is actually faster to move your mouse to each of the slaves windows, and manually target the AoE.

If you are really into mouse broadcasting, I'd look at HKN.
Grab a script purely for mouse broadcasting.
And continue to use KC for the keyboard stuff, since you are used to it.

Or alternatively, move entirely to HKN for everything (if you are comfortable with editing scripts).
Or look at IS Boxer, if you're not.