Please forgive the painfully ugly trackpad drawn sketch. I hope it makes sense too.
I'd sew the white portion onto a piece of black that will be the front half of him. Then I'd cut an identical black piece (the dotted lines in the drawing) and sew around while sewing his wings into this seam as well. Then follow that by sewing a circle onto the bottom. And of course, it's always easier to sew the face on before closing the plush.
You might have to play with the body pieces a little to get them to make a fat enough plush, but it can be done. Plus, if you use fleece instead of felt, you'd probably get a smoother, more rounded shape when it's stuffed. Fleece has more stretch to it where felt barely has any.
Another way you could do it, but it wouldn't be as clean and smooth would be to sew a tube out of black for his body and then gather the top in to make the top of his head. That could have a cute homemade vibe if you are into that.