Arrow , I hate to tell you this but before you sew it up you should have glued the lining to your pouch body. I use a contact cement or some kind of carpenter white glue. spread the glue on the flesh side of your leather and if you have a brayer or some kind of roller, smooth out the cloth and get out all of the wrinkles. From what I can see of your photo's all is not lost. The flap cloth can still be glued to the flap. If you are going to leave the flap as it is shown, spread on your glue and attach your cloth, smooth it out and press it with a weight until the glue is set.
I suggest that you look at some pouches and find you a design for your flap and just copy what you like. I sometimes saddle stitch around the edge of the flap and cut the lining about 3/4 of an inch around the edge and fray out the material leaving a fringe. If you want it a little shorter just trim it to your liking.
If you don't have them I suggest you get Tim Albert's book on creating hunting pouches or Ken Scotts DVD on Recreating the Kentucky Rifle Hunting Pouch. I have both of them and they are a world of information.
Kind Regards
Frank Barker
