Unidentified snippet theories

So, I've been compiling a mental list of theories about Cassie Clare's "unidentified snippets" for a while now, and I think it's time to write them down. So I can either say "I told you so" when I'm right or, you know, lie and say "my idea was better" when I'm wrong.

To my son,
If you are reading this letter, then I am dead.
Well, Cassie has explicitly stated that one version of City of Lost Souls is going to have a letter from Stephen Herondale to Jace as an extra feature. So I'm guessing this is the beginning of that letter.

"In your eyes, I have always found grace."
This sure sounds like something Jem would say to Tessa. But if we're thinking outside of the box, it could be something Magnus says to Alec if Alec's having one of those moments where he's jealous of people Magnus has had feelings for before. He knows about Will and has never gotten a straight answer regarding him, so he probably has more questions to ask. My out-of-the-box theory about this is that Alec asks how they look alike, and Magnus explains the eyes and the hair. But then he obviously has to say something to explain why he's in love with Alec and not Will, so he states the difference. Alec's eyes could possibly have grace, while Will's never did. I'm not just spitballing here; it could be true. Will has never exactly been known for grace.

He stopped dead. "Tessa told you?" he said.
Now, I have two different theories for who "he" is, but I get the strange feeling that the "you" is Sophie (my initial panic was that "he" was Will and "you" was Jem, but I'm pushing that thought down). It's probably either Gideon or Will speaking. If it's Gideon, he's probably talking about something we find out later, and if it's Will, he could be talking about... you know... The Thing. I mean, Sophie is the one who came and helped Tessa when she burned her hand on the fire stoker. It's possible that Tessa could finally give in and tell Sophie why she really did it, because she knows she can trust Sophie to keep it a secret.

his parabatai rune was bleeding
Hokay, so, my first thought for this one was "well, the H in 'his' isn't capitalized, and there's no period at the end of it. So it's not a whole sentence, and therefore there is more to the sentence, and therefore it's not as dramatic as it sounds." But who am I kidding? It doesn't matter what the rest of the sentence is, because this part is A BIG DEAL. I am about 70% sure this is Will/Jem and not Jace/Alec. Oh the implications! It could be a literal bleeding from battle or an attempt to disfigure the rune (WHY?), or it could be a figurative bleeding because the partnership has been injured (NO!), or it could be both. It is probably both.

Marry me today.
Initial thought: Jem is dying. Jem and Tessa are already engaged. My thought now: I'm not going Infernal Devices on this one because it's too painful. I'm siding with the person on Tumblr who made a nice piece of art featuring Magnus and Alec.

She slid the gold ring back on her finger before heading into Jace's bedroom.
Well, I doubt the Morgenstern ring actually fits Clary, and I see no reason why Jace would have proposed to her. I'm going really out-of-the-box and saying that Jace finds out that Tessa is his great-great-great grandmother (I will hold on to this possibility until it is explicitly confirmed that Tessa is a warlock) and the "ring" in question is a Herondale ring Will had had made for her when they (inevitably) got married. Jace has invited her to the New York Institute to ask her about something important, considering she knows a lot about the Herondales and can probably explain that whole Silent-Brothers-have-ties-with-them thing. I mean, I can't say I know why Jace would care about that, but I still do. Wishful thinking.

Will's hand looked brown and sunburnt by contrast, their fingers dovetailed together like piano keys.
Okay, this is kind of a lame unidentified snippet. The only places my imagination will allow me to go with this is that Will and Tessa are holding hands, or Tessa is observing Will and Jem holding hands (because Jem is probably dying... *sobs*).

He kissed each finger, and with each of them spoke a word. Five fingers, five words. His last.
AAAHHHHH. Once again I'm trying to think of a possible City of Lost Souls scene here but coming up with nothing. I can only picture Jem lying in bed holding hands with Tessa on one side and Will on the other and the five words are "Take care of each other." Or maybe "We will be together again."

"Did you..." he could barely bring himself to ask. "Did you like it?"
"Yeah." Her voice was husky. "I liked it."
LOLZ. I can imagine the fanfics about this one. "He" is probably Simon, because scenes with Jace and Clary are not usually written from Jace's perspective ("he could barely bring himself to ask" vs. "her voice was husky" --the narrator is definitely in "his" mind, not "hers"). I'll let you draw your own conclusions about that one. But it could also be nothing like that. Say, for instance, Isabelle has tried some strange vampire thing because she and Simon are obviously developing a little something-something. And "he" is Alec or Jace.