edit stage: it doesn't really matter all that much to me with regards to compression at that stage because i prefer to keep my eye on the prize (as it were)... and that is capturing the greatest performance i can get out of the talent.
tuning stage: i edit in autotune's graphic mode. i fix timing first using elastic audio, then pitch correct and in that process i will send the autotune track out to a new mono audio track with a rough draft of compression. in most cases i will print the tuned vocals to that new audio track and "hide & make inactive" track with autotune so that it does not occupy any voices. once the tuned/timed vocals are printed to new tracks, it will allow me to focus on the arrangement. comping is an art form in my opinion and sturgis is da vinci at this (also in my opinion). i will most likely tune/pocket vocals i might not even use so, needless to say that part is agonizingly time consuming but i have gotten a lot quicker and can probably time/tune/comp an entire song in about 30-45 min (no need to brag though).
while tracking vocals, i guess i don't really care how the monitors sound... my primary concern is how the talent is performing (delivery) so it is important that they (the artist) really likes the way they sound in their headphone mix (in my personal experience). a singer will be tons more confident if he/she sounds like a god in the headphones, so it needs to be as loud as they want, as affected as they want and as compressed as they want.
hope this answers some questions, but i will stress that the decisions i make with regard to vocal tracking works for me... but i am not totally sure they will work for you. either way, good luck man!