My personal opinion is that they're alive. You can easily explain Matsuri being alive, there's plenty of predecessors that keep characters alive through scenes like that.
Yorito, now that's a little more tricky. What I'd bet on is that the *real* Yorito is a Yaka somewhere. It would be simple to write that into the story I think, after all Matsuri herself said she "never found his body" in an earlier episode's flashback. There's plenty of room to have him be a Yaka in a second season or something, no paper Yorito's necessary!
:P
On the episode itself though, I was really saddened/disappointed by the ending until the cans shot. I hate animes that end sadly like sola did. I'm the type of guy who always wants the protagonists that I like to succeed in the end, it's just not enjoyable afterwards if they don't. That's why I'm nursing a small hope for the 2nd OVA at least, and maybe a 2nd season because of the 2 cans scene.
Personally, I hate Aono, I think she's selfish and definitely didn't deserve to claim both Yorito and Matsuri's lives for the sake of her happiness.
Love Matsuri though, her character makes me so sad though, the way she's alone.
