Just reiterating, you should be using /follow (alt-f is the default keybind) to have the slave follow the master. You really don't want to be turning on mouse repeater most of the time. Jamba should be handling most of your quest acceptance dialogues and things

to start with just use the normal keymap as set up and put the abilities you want to start with on keys 1to - (I use "=" as interact with target... which has to be set up in the keybinds menu on every character. This way = will cause the slaves to assist off the master and interact with their target. Almost exclusively the way I interact with the world).

As long as both characters have fireball on the 1 key for example, both toons should shoot the same thing.