If you have performed everything correctly (all your allies are loyal and went through the Omega 4 Relay the moment Shepherd returns to the ship after the crew is abducted) and made the correct companion choices in the Suicide mission, everybody will survive.
Your team: Anybody who's loyal (I usually go with Legion and Miranda, 'cause I love seeing her give lip to The Illusive Man and Legion is just awesome).Zaeed boasts the highest damage and Grunt has the highest health of all companions. It gives you a challenge that's fun, rewarding, and at times. However, Insanity provides more than a measly achievement. I think it's safe to say that Mass Effect 2 isn't the most difficult game out there if you're playing anything below Insanity- enemies just get general buffs but that's about it. This takes care of shields, rips armor, and isn't too bad against barriers. Mass Effect 2 Companion Tier List- Insanity.
Two more Mattocks, disruptor and Inferno ammo, Heavy Inferno Grenade, and two lv. Your Team: Anybody else (I usually go with Legion and Thane, but that's just my choice) For me, the best companions are Grunt (w/both vitality upgrades) and Zaeed.Escort: Mordin - if you do not send him back with the crew, there is a good chance he will die later on.Fire Team Leader: Garrus, Jacob, or Miranda.Specialist: Tali or Legion or Kasumi, if you have the DLC.
In order to have the best possible ending, you need to take the following choices: The suicide mission has 3 parts: Infiltration, The Long Walk and Final Battle. You need to recruit and perform Legion's loyalty mission last, after completing everybody else's loyalty mission, as well as upgrading your ship's armor, shielding and main weapon, so that you go through the Omega 4 Relay as soon as the crew is abducted. Yes, it is possible to save all of the crew.