The series will end with Al restored, his body at its proper age, but with Ed still in possession of his automail limbs. Here's why:
They're not going to create new limbs/Al's body from scratch. Since they've got the PS now, which (in theory) has absolutely no limitations, they probably *should* be able to create flesh from nothing, but I don't think that's what's going to happen. They're going to use the PS to retrieve Al's body from the other side of the gate. Because, as we learned from the Wrath arc, it's still there. It didn't disappear or decompose or anything, it was just taken to the other side of the gate. And not only is it still there, but it's aging at a normal rate, the same way Wrath did while he was beyond the gate.
(Which leads me to wonder if he's stopped aging like the other homunculus, now that he's in the real world. Hm.)
But anyway. So they're going to retrieve Al's body. But they *can't* retrieve Ed's limbs because, well. Wrath's got them. It's not like Ed can rip them off and reclaim them. Those suckers are beyond his reach now. They're part of someone else's body. ...you know, Al is pretty lucky that Wrath didn't just steal his whole body, as opposed to just Ed's arm and leg. Then they'd be screwed.
As for everyone else-- oh man. I'm so afraid. ;_; This show has such a huge cast... People are going to die. I feel that's certain. I just don't know who, which is very nervewracking. However, the fact that Roy does the voice over for the movie trailer makes me sure that he survives the series. Maybe not intact (;_;) but he DOES survive.
There are so many military characters, character's whose *job* it is to put their life on the line for civilians, that I feel sure that some of them are going to die. And it pains me to say this, but I have this sinking feeling that they're going to kill my Maria. Obviously not in the manner that they did in the manga, but the fact that they DID in the manga certainly doesn't bode well for her continued health. There's also the fact that people with familial or quasi-familial relationships with Ed and Al have a pretty bad track record. Mother, dead. Little sister Nina, dead. Father figure Hughes, dead. It's part of a "Ed brings misfortune to those who love him" cycle of ANGST. Oh Maria. Please don't die. Pleeease.
Although I'm am 100% certain when I say that Winry will not die. The series could end in a giant massacre with only Ed and Mustang surviving (since the trailer officially confirms that atleast the two of them live) and Winry would remain untouched. This, I know.
It seems to me that these are obvious conclusions, but the fact that nobody else seems to think similarly makes me question that. What do you think?