Well it'd depend on what game and if you added live to an original account with a saved game OR if you have a separate account with live. As for a MW2 example If you add live on the same account it should save ALL progress If you want to transfer you'd probably have the campaign progress but no multiplayer online progress Check out xbox.com for more info.
To get a Xbox live membership, you need to register. Your profile must have been registered to go online.
No
No it does not sorry but if you have Xbox live gold for only one profile then it works ONLY with that profile.sorry :/
No, just change the email address in your Xbox live account.
You Can't I'm Sorry :(
You can create your a profile and made it silver.
you go on profile and then recover gamertag
Yes, you just need to transfer the profile.
You go on download profile and type in the email address and the password for the email address which you used on the account
This question is better answered by a customer support member from Microsoft's team, however, I think your best answer would be that it not be possible if a membership has already been added to an account.
No, once you buy an Xbox Live subscription and put it on an account it stays on that account and can't be transferred.