The Old Testament is full of wars that I am sure he participated in, one way or another, direct or indirect.. 

Yes, but that was after the Earth was formed.  He was speaking of before that.

So, if she feeds on the Winter Knight mantle, she perhaps becomes a suitable vessel for fae power?

That assumes she can feed on a mantle.  Nothing we know says they're made of life force.

You're answer seem to be to the point that Mira is making i.e. that Vadderung isn't human/mortal. To which you respond as above, implying (I believe) that you need to be mortal to use soulfire which is of course isn't true, as the quote from Small Favor proves. But perhaps I misunderstand you?

I was just responding to the conclusion that he doesn't have a soul. I wasn't even paying attention to the whole "used to be mortal" thing.

And to be precise, it was the Eye of Balor that was powered by fear.

It was hate, not fear:

“The Eye,” I said. “It was made of pure hate. I felt that.”

Butcher, Jim. Battle Ground (Dresden Files) (p. 394). Penguin Publishing Group. Kindle Edition.

...have a soul?  Per WoJ, he has Soulfire, and the fuel for that is your soul, so it seems like he must. Which raises the question: if so, do gods in general have souls, or is Odin special?

Lea offered to show him how she did it.  Harry turned her down:

“I lulled their predator spirit to sleep,” she said calmly. “Poor lambs. They didn’t realize how much strength they drew from it. Mayhap this will prove a useful lesson.”
I frowned at that. “You mean . . . the vampire part of them?”
 “Of course.”
I sat there for a moment, stunned. If the vampire infection within half vampires like Susan and Martin could be enchanted to sleep, then it was presumably possible to do other things to it as well. Suppress it, maybe permanently.
It might even be possible to destroy it.
I felt a door in my mind open upon a hope I had shut away a long time ago.
Maybe I could save them both.
“I . . .” I shook my head. “I searched for a way to . . . I spent more than a . . .”
I shook my head harder. “I spent more than a year trying to find a way to . . .” I looked at my godmother. “How? How did you do it?”
She looked back at me, her lips curled into something that wasn’t precisely a smile. “Oh, sweet child. Information of that sort is treasure indeed. What have you to trade for such a precious gem of knowledge?”
 I clenched my teeth. “It’s always about bargains with you, isn’t it.”
“Of course, child. But I always live up to my end. Hence, my protection of you.”
 “Protection?” I demanded. “You spent most of a couple of decades trying to turn me into a dog!”
“Only when you strayed out of the mortal world,” she said, as if baffled at why I would be upset. “Child, we had a bargain. And you had not willingly provided your portion of it.” She smiled widely at Mouse. “And dogs are so charming.”
Mouse watched her with calm, wary eyes, his body motionless. I frowned. “But . . . you sold my debt to Mab.”
“Precisely. At an excellent price, I might add. So now, all that remains twixt thou and I is your mother’s bargain. Unless you would prefer to enter another compact, of course . . .”
I shuddered. “No, thank you.”

Butcher, Jim. Changes (The Dresden Files, Book 12) (pp. 135-136). Penguin Publishing Group. Kindle Edition.

Not just to punish both of them a bit for what they pulled at the end of Changes, but she now needs more than ever to send a message to the rest of the supernatural world that she is independent and a force to be reckoned with, as her grandmother was. 

Kincaid worked for her grandmother:

“No,” Luccio said. “But Kincaid was working for Ivy’s grandmother at the time, and the girl confided in him.”

Butcher, Jim. Small Favor (The Dresden Files, Book 10) (p. 408). Penguin Publishing Group. Kindle Edition.

While interesting, it doesn't address the question at hand.