Question about buying the game

The transfer cable is for transferring game saves mainly. Once you recover your gamertag, you can redownload all the DLC so you don't need the cable for that.

You can use your old hard drive if you buy an Xbox that is the same as your old one. If you're buying a new Slim and the hard drive is from the older models, then the hard drive is not compatible.

The transfer cable is only needed for transferring data from one hard drive to another. So if you were transferring your game saves from your old xbox hard drive, then you would need a transfer cable or flash drive. Otherwise, you can just follow GreyPilgrim's
advice and you'll be all set.

As long as you are using the same account you used to initially purchase the DLC yes you can download it to your new console.

Firstly recover your account to the new 360, then just go to account management and select 'download history', it will all be listed there and you can re download it for free.

If you are using a new console you will need to transfer the DLC licences to it, or you will not be able to play the DLC offline.

It will only charge you for the first 12 months. You would need to turn off auto-renewal before the 12 months ends so it doesn't automatically charge you for another 12 months.

Thanks for the clarification

It will only charge you for the first 12 months. You would need to turn off auto-renewal before the 12 months ends so it doesn't automatically charge you for another 12 months.