M effect 2 Suicide mission?

I'm trying to get the achievement where everyone survives the suicide mission. I completed Legion's loyalty mission and it was my second to last one. I got back to the ship where he and Tali were fighting, arguing, whatever. Apparently my renegade wasn't high enough to use the renegade dialogue even though it was over 75%. Is there any way to get his loyalty back at any point? And if i decide to take Samara's daughter instead of her, will she automatically be loyal?