Thanks so much for the many replies. I, actually, have been so swamped w/work I haven't had a chance to check back in but definitely have good news to report.
I decided to cook this for Thanksgiving and so far, it's REALLY worked out well. The filling is done (as we talked about here, poached the skinless chicken breasts--with bone-- with broth, fresh & dry herbs, wine, onion, etc), sauteed the celery, carrots, extra vidalla onion, garlic, shitake mushrooms & a bit of kale in olive oil, herbs a little more wine. Chopped the chicken, reserved about 2 cups of the broth, added butter, heavy cream, a little grand marnier, spices to taste and slowly blended everything, adjusted the spice. It really tastes spectacular and is chilling in the fridge. There are DEFINITELY many many flavors in it, it all works. I happen to love cooking without a net (worst case scenario, I do things in advance so if something doesn't work out, I have time to re-do or go back to something I've done tons of times) so it was thrilling to do!
I ended up buying Kronos filo (mainly because I've been so busy w/work I didn't have time to find a restaurant or specialty store and I'm near Fairway here in NYC.) I'm sure it'll be fine. Because it's Thanksgiving, I didn't want to do a traditional chicken pot pie and think this will be a bit more festive. (Normally, I'd do a pate brisee as the crust.) I'm brushing the filo w/melted butter mixed with a little olive oil.
Guests are arriving tomorrow at 6pm, so I will assemble it at around 4:30pm-ish, adding the petite peas and filo, and refrigerate for about an hour and a quarter, with just a plastic wrap on top before popping it in the oven around 6:15'ish. Serving dinner at 7pm. I'm serving it with Champagne, a chilled cranberry sauce (with orange & lime zest), and a salad with arugula, frisee, orange grape tomatoes. For hors d'oeuvres, bruschetta with goat cheese, tomatoes and crispy, sauteed chorizo.
My friends & I wanted an unorthodox Thanksgiving and I think this'll do the trick.
Thanks so much for all of your great suggestions! Wishing you all a wonderful holiday.