Your conditionals could be in the wrong order - the way you wrote those macros, you will always attack your current target if you have one. My impression is that you'd rather attack your focus's target by preference. If I'm wrong and you only want to assist your focus if you aren't currently targeting anything, then the macros will work as you wrote them.
You mentioned "assist my focus if it's alive and friendly". The way you wrote the macro, it's actually checking your focus's target. If that's your intention, fine, but you cannot conditionally cast on anything other than the unit being tested in your clause. The following would work, however:
/cast blah blah
As long as none of the abilities/items you are activating invokes the global cooldown (self/item group cooldowns don't count), one press will cause all of those commands to be run at the same time (more or less).
It is possible, but I don't have my API reference handy to tell you exactly how to write the command. You would use /script SetBinding(), however. I'll check when I get home. I'm also not sure if it's possible to do this in combat; I suspect not.
Using a voice program to control the game is fine, as long as you stick to the "one command = one keypress" mantra. Having a voice command hold down 'W' until you tell it to stop is no problem. Having a voice command send "1, pause, 2, pause, 3, pause, 4, pause" would be a nono. Voice programs are no different in this manner than a programmable keyboard, mouse, or other peripheral. It's how you use it that counts, not that you use it.