Fire Daemon said:
No there isn't anyway to get her loyalty back*. To keep Miranda alive don't give her any jobs on the suicide mission and don't take her with you to the final boss. I'm not 100% sure if that will save her but people only seem to die when you give em jobs. I have heard of people dying randomly but it seems to be rare. You don't need full loyalty to come out with everyone, I know that for a fact.
I was lucky though, I always have enough Paragon/Renegade points to do the impossible. Screw Neutrality!
*Edited.
Also, if you do Jack's mission first and side with her can you then go and do Miranda's and gain her loyalty as well? I've never tried that.
1. Dying depends on a lot of factors, loyalty, who the other people are in the squad, etc. Miranda doesn't die if she leads the first alternative team, for instance.
2. Side with Miranda, then go tell Jack that you were just lying to shut her up. You can do a similar thing with Legion/Tali by siding with Tali and telling Legion that you were just lying to shut Tali up.
3. They only start fighting after you've finished BOTH loyalty missions. So there's no way to side with one before they are both loyal. Same with Tali's mission.
Or use paragon/renegade.
If not those... then I think you're screwed. If you want them to live even though they're not loyal, then I wouldn't take them anywhere or give them any jobs in the final mission, as was suggested. Just to be safe.
CmdrGoob said:
Mordin IS a wimp, he has a quite high chance of dying in the final act. The best thing to do is to have him lead the survivors back because that way he will definitely survive.
I like to take Mordin with me to the boss fight. He's incinerate makes really quick work of Harbinger whenever he decides to pop up. Mordin survived when I took him and Samara to the final battle.
I always wondered if the teammates surviving that final battle has to do with researching enough health boosting upgrades and what not. Because I've seen the cinematics where they die, and they essentially get clobbered by the debris you pick off of them in the cinematic. In my game they stood up and they were fine. On youtube, it looks like they're too injured and die.
6 minutes in: http://www.youtube.com/watch?v=pRHhdc53Od8