I think it would be fine for all of that as long as your headphones are bud style and not the big cuff style. I don't like earbuds and prefer cuff style headphones and there is not room in the bag for them. There will not be a lot of extra room but should be fine.
I carry ipad, kindle, four extra batteries for phone and wireless router (and the wireless router and modem), kleenex, gum, pens, camera and a few other odds and ends.
I carry ipad, kindle, four extra batteries for phone and wireless router (and the wireless router and modem), kleenex, gum, pens, camera and a few other odds and ends.