I just yesterday beat Mass Effect 1 and loved it so much that I started a second playthrough almost immediately after the credits rolled. Soon after I started my second playthrough I wondered what would happen if I took the second playthrough save, while still in mid campaign, and integrated it into Mass Effect 2. To keep my options open in case what I fear happens (which is that Mass Effect  will only take the decisions I made so far on my second playthrough and not what I have done on my first playthrough) I started my second playthrough on a separate save slot away from my first playthrough. So, my questions are the following-
1. If I integrate a mid second playthrough save slot into Mass Effect 2, will it take all the decisions I first made into account or only the ones I have made so far on the 2nd playthrough?
2. If I fully complete a second playthrough, which playthrough does Mass Effect 2 import? 
(I apologize if 1&2 sound like the same question).
3. Before Mass Effect 2 starts, does it tell you the decisions you made in the save slot you are trying to import?

You can't really import non-completed saves as far as I know. When you import, it'll ask you which save to import, then show you what you did in that save before asking you one more time to confirm that you want to use that save.

You can only import a completed save, and it'll import the latest playthrough you've gone through with that Shepard career. It'll also run down all the major decisions you made aswell, though most will be brought up through countless emails in yah inbox -_-

You can't import a mid-game character as far as I know, you can only import the save you get when you beat the game. If you play it twice, it will take the 2nd playthrough's choices, if you choose to import the save from the second playthrough. If you take the save form the first playthrough, it will take the first.
 
Don't quote me on this, this is just from what I remember.