I know for a fact you can get FTL working with Keyclone.
And I know that I tried it a few times, and never managed to get it going.
There is a wiki entry for the FTL, if you care to mess around with Keyclone/FTL further.

IS Boxer is the simplest FTL, if you want another program.
During the wizard creation step, ensure the FTL (checkmarks) are different for each toon/slot if you change them, or leave them to the default settings.
Then, ensure you don't have any wow keybinds on Backspace (as that is by default an unbound key in wow, which is the default assist me key in IS Boxer).
And don't change settings for FTL inside of IS Boxer Toolkit... Three have FTL as "enabled" and everything else is "default".

Then you control any toon.
If you press "1", then each toon will do their move on "1", but auto assisting the lead toon.
You don't need macros on the "1", just drag spells right out of the spell book.