I Don't Think She's Alive
In Episode One, Faith states to Bigby ," I won't be doing this for much longer.." which made me curious. Then after playing through episode five and reading all of your theories, I believe I have my own. Faith, (and this is just a theory) was in fact dead before the game began. As Nerissa stated, "...i had to watch him do it in front of me," regarding to Faith arriving at the Pudding N Pie. We can assume that Georgie killed Faith upon arrival. Therefore, Faith could never have met Bigby. It has ALWAYS been Nerissa. In Episode One, Bigby gave "Faith" a certain amount of money ($48, $58 whatever) but we found that exact amount in Georgie's floor safe. That would mean that "Faith" had to have given the money to him before he removed the ribbon. In my opinion, I can't see Georgie being a cruel guy after witnessing his behavior toward Vivan's death. He had to have some care for his girls. In addition, Nerissa said that Georgie was going to smooth it out, meaning he cared. I doubt he asked for the money from "Faith" and then killed her, that'd be too selfish of him.
Therefore, Nerissa glamoured herself and became Faith to catch Bigby's attention and lure him to Woody's, which is why she told," I'm not gonna be doing this for much longer." foreshadowing what will happen. Most of you have already mentioned this and I was just trying to put some add-ons. I think we're onto something. Although, TellTale will always make us question our own theories. 
What'd you guys think? I'm open to any and all criticism and any flaws that I have.
Also! Am I the only one who noticed that damn cab kept shooting by Nerissa and Bigby at the end of Ep 5?!?! That Ginger Mother Fudger.
Comments
I don't know why she'd tell Bigby about the head but not about being glamoured. She had no reason to lie if she was Nerissa, many reasons to lie if she was Faith. That's my only big beef about this theory. Also the donkey skin quote near the end to me seems like it's pointing towards faith escaping. But this is just my interpretation, if Nerissa was Nerissa the fade to black would have been silly, all the unanswered things could have been answered in 10 seconds if she was Nerissa in the end and just glamoured as faith in the beginning. My last 2 cents about the ending for now
"these lips are sealed". Have you forgotten? The same way she lead Bigby to the hotel so he could find out for himself, she placed Faiths head at Bigbys doorstep just to help lead him in the right direction.
In the end, she confessed everything when the ribbons weren't in effect anymore. Why would she not have told that when she told about bringing the head and lying in the court, which both were "bigger" things to confess.
You're definitely right Jayonnaise. But then again, why would Faith compel herself to be so selfish and let Nerissa die? Lawrence said she cared about him and others. She wouldn't let Nerissa die...would she? Faith IS the one who took the photo.
The same way you might not tell everything you know to everybody. Not much to say.
Nerissa* Faith is dead before the episode is even started. Nerissa is alive and well, you saw her walk away in end did you not?
That doesn't necessarily MEAN its her. (Although I hope it was) there's a possibility it was Faith, but I just doubt it.
I was thinking exactly like you, but something is disturbind my mind. As Kakulukia said:
My guess is Faith glamoured Nerissa's body to look like her so her cover wouldn't be blown.
[...]
I might be completely off base, but why would they have made that character Donkeyskin if she's not going to disguise herself?
Maybe nerissa was glamoured as faith for some reason, was murdered unwittingly and faith, not wanting georgie to realise the mistake and correct it, pretended to be nerissa from then on. Although this wouldn't make sense with the pronouns she was using at the end (if she was speaking as herself - faith - then if she told geordie about the plan then she probably wouldn't have been the main target and if she was speaking from the point of view of her alter-ego - nerissa - then she wouldn't have been the one who left the severed head on the steps).
Then why speak to him at all? it doesn't make sense that she would admit she dropped the head to lure him into the investigation, but not she glamoured as Faith to do the same. It's pretty pointless not to, if that's the reason. Why bother dropping the hint phrase 'not so bad' at the end? She is more involved than simply 'I lead you on a trail' person.
Then what is this possibility? Everything points to what i just told you.
It's not pointless. She just did not want him to know about that, the same reason we all keep secrets from each other regarding all kinds of things. She choose to tell him parts of it but did not want him to know the whole story. That's common in life.
Yes, that does not make sense.