Why not set your leader as focus and then base every spell off of assist focus? If your leader dies, press one of 4 buttons to assign a new leader and everything resets nearly instantly and you keep right on going. You would need only work out movement (perhaps a dedicated directional keypad for each?)

Only downside is you lose focus for other uses.

You COULD hardwire everything in to support absolute targeting and have a mod or left and right alt/shift/control toggles to select different leaders based on various combinations of keys you held (or toggled) down.

But using focus seems like far less work and far easier to use.