I just finished Mass Effect 2 and wished that I had done a few things differently (loyal up team members), when I beat it I had the option to start a new game with some bonuses. I get to keep the whole arsenal of weapons, extra credits and level of powers. When ME3 comes out later this year which profile will import to ME3, the relationships/conversations paths I made the first time through or the second one I'm playing now? See the first time through the non-loyal team members died at the end and I'm hoping the second time through ME2 I can change the outcome. I'm hoping the second time beating ME2 overwrites the first profile.
With Zaeed, you must sacrifice the workers at the refinery to get his loyalty. I can't remember how you get Jack. Check the mass effect 2 wiki and it will walk you through how to get everyone's loyalty.
Yes, there is. You have to assign the right person for the right job at the end. I think I sent Tali throught the piping/ducts. I made zaeed the commander of the 2nd team, and he died, but I didn't like him anyway. I took Grunt and Jacob to the final battle and they both lived.