Suicide Mission Loop

@WreckGar2457  If you do anything else after your crew is captured, half of them will die, there's no getting around that.  If you have Kasumi and she's loyal, she can handle the vents instead, and she'll survive if you also pick the right person to lead the other team.

There's a flowchart here with all the options:

https://biowaresocialnetwork.boards.net/thread/51/me2-mission-guide

It will spoil things if you look too far ahead, so be careful if you'd prefer surprises.

Your other option is of course a save editor.

Can Tali go on the sucide mission not loyal and survive?

@WreckGar2457  The only time a specific team member's loyalty matters is if you give them a special assignment, for example Tali in the vents or whoever leads the strike teams.  Other than that, the only other time loyalty matters is for the final hold-the-line team, and there it's the cumulative defensive capability of that team that determines the outcome.  If they're above the limit, everyone lives; if not, people die in a particular order.

When you send a team member back with the crew, don't include Grunt, Zaeed, or Garrus, who have the best defensive capabilities and who you'll want holding the line.  The team member you send back won't be available for the rest of the mission.

So, for the final battle, when you can bring two teammates, and the rest hold the line, make sure the two you bring are loyal.  Assuming Tali and Legion are the only non-loyal teammates, and you have all 12 teammates in total, you can bring two of Thane, Samara/Morinth, Jacob, Miranda, Jack, Kasumi, and Mordin along with you, and the rest will be just strong enough collectively to keep each other alive.  This is a reading of the chart I linked, if you want to double-check the math.

The important thing to remember is that you CAN keep everyone alive as long as none of the non-loyal team members have to do anything special.  And leave the intimidating hulks (Grunt, Zaeed, Garrus) to hold the line so their defense helps the rest of the team.  Your character won't particularly need them as long as you're good about using the others' special abilities.

In the original ME2 if you recruit Legion and immediately talk to him about his loyalty mission and accept it, you can do it before your crew is taken, even if they should....it delays the taking until after Legions.  So if you have a save from before your crew is taken, you should be able to do Legions if you wish. 

I recommend sending a loyal Mordin back with the crew, leave the heavy hitters at the line and take squishies that are loyal with you on final battle....for me that is usually Miranda and Thane.

Ok first off it sounds like a newbie. Second it takes some math involved, and thirdly you are waiting way too long to get ready. My advice is to sacrifice the colonists and What ever you do DON'T INITIATE THE FINAL SUICIDE MISSION UNTIL YOU ARE READY. Also there is a way to get Miranda and Jack and Legion and Tali to put aside their differences and still be loyal but it requires a maxed out Paragon or Renegade Score of 100%  The Same WithMass Effect 3 where you can stop the war with the Quarians and Geth. This is what I have done and it helps. I have been playing Mass Effect for years and know the ins and outs and everything else of the games! 

@Darthvader99076  Gee, I've only played Mass Effect 2 once, but this hasn't been my experience at all.  I convinced Miranda and Jack to get along, and Tali and Legion too—as in, both pairs stayed loyal—without a maxed out Paragon or Renegade score.  And there's barely any math involved in the final calculations, just some basic addition.

Oh, and the original poster played through the mission over a week ago.

Ok I swear by this and it helps : https://gamefaqs.gamespot.com/boards/944907-mass-effect-2/57299394  this is from 2012 but still valid!!