Assuming you mean wear of the edges of the tires, and not the middle, this is an issue of UNDER inflation of the tires.
Possible alignment issue.
Yes, cupping is caused by defective shocks/struts.
Can I use 245 70 16 in an 2003 tahoe
NO
Tires need ballanced!!!
Yes, it can but cupping can also have other causes. Over inflated tires can tend to bouce more, especially when combined with weak/worn shocks or struts. When tires bounce cupping can occur when the tires strike the road. Cupping can also be caused by the tire/wheel assembly being out of balance (which can also cause the tires to bounce). Cupping is just one of several types unusual wear on tires.
If you are driving in 4 wheel drive, put them on the front tires. If you are driving in 2wd ordon'thave 4 wheel drive, put them on the back.
Cupping of tires indicates many of things depending upon where the cupping is. Center tread cupping is a sign of under inflation or bad shock absorbers while cupping on the edges can indicate bad wheel bearings, bad ball joints or bad steering.
Ford and Chevy parts will not interchange, SORRY
make sure that the tires are all properly inflated. If they are, then you may need to have the front end aligned.
Check the tires for cupping. If you have had an alignment problem the tires could be cupping and will make quite a lot of noise. It could also be a wheel bearing.
Tires out of balance, Bad tie-rod ends. Steering stablelizer shock, Bent wheel, Belt broken in the tire. Bad idler arm. I would have the front tires balanced first.