No, Live memberships are non-transferable.
Yes, a membership is required for Xbox Live features to work for the console and account.
It should be activated as soon as a member has added membership to the account.
No, Achievements can be earned online or offline. If you join xbox live with the same account, the achievements get transferred to the online account.
There is no reason for downgrading a Xbox live account. If people who do not know what downgrading an Xbox live account means, it will mean that your gold membership will become silver. However, there is no way to do this and there is no reason to do so.
You need to buy a live membership card from any game shop or online games store. This card will have a code on which you input into your xbox and that will give you a live membership. The cards are available in 3 months, or 12 months, if you want to have keep your live membership you will need to buy a new card or set up an automatic credit card account.
yes your membership will go with your profile but you cannot go from xbox to 360
No, I'm sorry to tell you this. Actually, you can join it for free and use a Xbox Live trial membership, however, after that runs out, the account is made a silver membership until the person(s) can purchase gold membership again.
When you create an account on your console it automatically becomes an Xbox Silver Account (free account). But you can purchase an Xbox LIVE Subscription which you can't get for free.
you can not play online on a free account, but you can download demos and stream movies
When you create an account it will give you the option of buying or redeeming a subscription card.
You will need to go on the Xbox website. From there, you can create a Xbox live account or use an existing account and input a Xbox live membership.