Your plans for the quail sound ambitious. However, they sound delicious, so if you have already got them marinating, go forward.
If you want a demi-glace type sauce from the bones, etc. you will need a bit of enrichment from roasted, browned and stewed chicken, duck, or even veal bones to get a thick stock going. First, make a mirepoix add it to enrich the meat stock as it boils, and strain it out before the final thickening of the stock. You could also reduce some red wine to a tablespoon or so and add that to the sauce/glaze. But you will need to taste to get the balance right, or the wine will dominate.
Given the small amount of meat per bird, you might be just as well off with a somewhat simpler approach.
One of my favorite things to do with quail is to marinate it in Cavalchina rose (the wine--minus the accent on the e) and pine forest honey for several hours or overnight. Then I dry, salt, and grill them and serve on mixed lettuces with a light vinaigrette. Or, I stuff the boneless birds with rosemary branches and wrap them in pancetta, secured with toothpicks, and grill them. They are good this way served with a slightly bitter lettuce mix with frisee and radicchio, and a stronger flavored vinaigrette. It is also nice to make some croutons to set them on and absorb the juice-- with or without the lettuce.
Sounds like a wonderful dinner. Enjoy.
Man : I can't understand how a poet like you can eat that stuff.
T. S. Eliot: Ah, but you're not a poet.