I lost Miranda's loyalty over Jack and even though I was just about full on paragon, I still didn't get the convo option to make her loyal again. You must have to have full Paragon status to do so. I think I did after the game, but then she talks about the Collectors and says we can talk later. She was so cold and nasty to me before

. However, having that one non-loyal member made no difference in squadmate survival. I made sure not to use her for anything, though, just in case. I had Garrus lead both secondary squads, used Samara for the barrier, sent Zaeed back with the crew, and kept Mordin and Legion with me both times. I thought the part with Samara might be tough to get through when husks start running at you, but there really aren't that many. It seems like they could have made that much harder. They were much harder on the IFF mission for example - just tons of them around you at points, especially at the end when you find Legion. I had more trouble with that one (and Legion's loyalty mission) than the endgame. I also thought the valve section might be much tougher and at one point I did have Tali down in the red (a timer came up with 20 seconds left at that point). But the valve was right in front of me so no problem. It did seem like I didn't get anywhere near 8 and then it ended though - that was odd.