I do not think so because the 3G is rounded and the iPhone 4 is not, so the corners would not match up properly.
No. Since they have different shape
The iPhone 5 is shaped differently than the iPhone 4, so the case would not work. It may fit, but it wouldn't be as snug as a fit as you would want. It is usually better to buy the case for your specific iPhone.
they are different in size and shape, can't you replace iPhone 2G case with iPhone 4 case.
No, they made the iPhone 4 case for a iPhone 4 not a droid.
yes.
Yes
No, the iPhone 5s, iPhone 5c and iPhone 5 do not fit into the same cases.
no
Of course not. The iPhone is a lot thicker.
No, The case won't fit. The iPhone 4 screen is 88.9 mm (3.5 in) while the iPhone 5 is 101.6 mm (4 in).
Yes the case will fit. All iPhone 5 models are the same size.
No. The iPhone 5 is physically bigger than the iPhone 3GS.