Wheel Noise / vibration in 2005 Prius, 145k miles

So about 6 months ago immediately after getting the tires rotated we noticed a whooping Noise and slight vibration that starts at about 25 mph and increases in frequency with speed. At above 70 vibration becomes more annoying. For turns at 50 mph and when slowing a whooping noise is particularly noticeable. Three tires have 30k miles on them and the fourth has 45k. We got the tires rotated 1 month ago ( 5k miles since last rotation) and noticed the problem became slightly worse.
So I took it in and they told me that the vibration was caused by front wheel bearings and it would be 1300 to fix. They also told me that my front passengers wheel had bald spots and this was caused by a warped rotor on the front passengers side (see pics). They also think the the struts are bad.
I agree that the struts are not what they once were and I don't think they've ever been replaced. I also have noticed that the front drivers wheel is the oldest one and also has worn spots. My question is, how can I know if the sound and vibration is a bearing problem or just a tire or strut thing. Also what is causing the bald spots in the tires? Do grippy brakes cause this wear or is it the struts or balance? If it is a brake issue I'd expect it to be rear brakes because the tires now on the front were previously in the back.