I was on swim team for six years and have taught several people how to swim, so maybe I can help.
When you do your freestyle, are you rotating your torso when you breathe in? I breathe to the left and take my breath when my left arm is at the height of the stroke, which automatically rotates your torso a bit. You're not trying to be flat in the water and turning your head. Use your body to turn your head and try to look up as high as you can, which will help you tilt your head up the right amount. As far as the legs on the breast stroke, that is an issue that I remember having to work out b/c I did the same thing with my legs being heavier than the top half of me. When your face is in the water, tuck your head down a bit and tilt your hips up some and try to let your legs skim the surface of the water. When you come up to breathe, you're not trying to lift your body out of the water, you're just using the pulling motion of your arms to get far enough out to get your chin above the water, then sort of thrust your head down when you push your arms forward.
For the backstroke, it's basically freestyle done on your back. The easiest way to do it is to push off the wall facing down (like you're going to swim freestyle), and then when you start to break the surface, twist yourself onto your back like you're doing a barrel roll. Then just stroke with your arms like you would if you were on your stomach. It's a little bit harder to get the hang of b/c your arms try to go out to the side instead of down on the downstroke, but just focus on keeping them as close to your body as you can. Flutter kick like you would freestyle. Also, every once in a while, tilt your head back so your eyes are under the water and look for the wall so you don't hit it. Or, mark a spot on the ceiling, if you're indoors, or look for a landmark (a particularly tall tree if you're outdoors) from which you can judge where the wall is and when you get close to that, you just put one arm ahead of you and kick and then your hand will slap the wall.
Hope this helps and makes sense, lol! It's easier to show than tell.