You will need the ship upgrades (except for med bay, probes and planet scanning) plus preferably full crew loyalty (though this is not a must.)
In terms of sqaud selection so long as you are sensible in giving jobs to those that are most relevant to it, it is straightforward enough. My selection was -
Legion as Tech Garrus as Fire Squad leader, both times Jacob to escort Normandy crew Samara as biotic My personal squad was always Mordin and Zaeed.
No one died at all.