Yes, they lost their faith, and had to roam for 40 years. That was their punishment for choosing to follow false gods, and for turning their backs on God. Fact is, didn't HE lead them out of the bondage of Egypt reguardless of their sins?
Yes, they strayed, and had to pay for it. 4o years.
If you read in Revelations, you will see that there will be a special group in Heaven, made up ONLY of 144,000. That's 12,000 from each of the 12 tribes of Israel.
I'd say God singling them out shows a special bond with Him.