Go light on #1, she already sounds awesome! Reverb pulls things into the background.
On #3 (the echo), think of it more like a background vocalist (in this case the same person) singing it. Just copying the original word, pulling it into the background and pasting it at the right point should work too. I'll see if I can find a quick example later today.
What you've already done may be enough for #4. And doing #2 may finish the effort.
#5 will put the entire song and every chord into
Am.
#6 & 7, just a thought that came into mind. Replace the vocoder with a Golden Throat fuzz lead (if you have access to a Golden Throat or similar - think Sweet Emotion, Do You Feel Like I Do, etc.)