A burning smell ... and bad shaking/humming noise sound from tires

bearings or cv axles, if they brake or zeize you could have a accident.

I found out on my 1999 mazda 626 that both the front and rear had to be aligned separatly. I had never heard of such I knew cars having only front ends aligned. My problem had been vibration at the rear and I took it in to the place I had purchased the tires and they told me both front and rear have separate alignment pachages.