I can speak from someone who used to believe as Halo did, but I don't think I do anymore. I once thought angels were separate beings, but I have recently had a mind altering event happen in my life and I'm not sure of any of that anymore.
I didn't mean that to sound negative, I just mean I believe that when we die, we get to come back to help be a guide to those we love. I lost my dad in summer of '06, and I believe he is still with me, visiting me in dreams and watching over me. I feel his presence all the time.
Do they become angels? I dunno, but it feels like it. The Bible says we have a great cloud of witnesses, who are in that cloud? Angels? Those that have passed on? A little of both?
I think they can see those things, but I believe they are surrounded with so much love and joy that they don't feel it. Their emotions, their love, etc., is far more evolved than ours is. They can see the whole picture, we can't.
That's just my dimestore beliefs, take it or leave it, FWIW. YMMV.
Barbossa, you DEVIL! I know some of those things you want to do!