Cardinals love black oil sunflower, especially kernals, and some will also eat safflower, although not as much as some think they do. They MIGHT dabble at the nuts and fruit, but I doubt it. In my experience, sunflower is their food of choice.
Chickadees are most likely going for the sunflower seeds, both in and out of the shell, and the peanuts. They may also dabble at the fruit, but I'd bet not.
Tufted titmice, from what I read (I don't get them here), are about the same as chickadees in diet, mostly going for sunflower and nuts. They also may eat the fruit.
Bluejays will eat just about anything they see, but in my experience go for any kind of peanuts first. They also gobble up corn, and seem to resort to eating the seeds after the nuts are gone, and prefer the larger seeds, like sunflower. I would suspect they might be eating the fruit as well.
On to the cowbirds. They are there for the millet, and probably the sunflower kernals. Cowbirds don't prefer to crack larger shells like sunflower, but will definately eat the kernals, and love millet and cracked corn. Should there be no other food source, they will resort to the sunflower in the shell, but not usually.
So, on to the big picture. As for the bird seed you're feeding, my guess is you are paying a pretty penny for it. Personally, I don't waste my money on "special" seed mixes. Most of them claim to attract more birds, but in most cases, those birds are actually eating the common ingredients, and not the fruits and stuff. The nuts are popular, but when fed freely like that, they just get stolen by the bluejays, who just go and stash them for later, so you get no pleasure from watching them actually eat. There are 3 things you can feed that will bring in 99% of feeder birds; black oil sunflower, white proso millet, and cracked corn. Most all birds will eat one or more of those, and obviously the useful bonus foods are niger seed, suet, and nuts.
So, personally, I buy the 3 main staples in bulk seperately, and mix my own seed. I also buy bulk out of shell peanuts, and feed them in a peanut feeder. I also feed suet and niger. I have various feeders of different types, and feed different seeds or mixes in each, depending what birds prefer to eat in that feeder. I actually attract more birds this way then when I used to buy the special mixes, not to mention I have no food being picked through or wasted.
Joe