One contract per applicant. In the application process, you will be asked if you have applied previously within the last 12 months. Technically, you have, so you will have to answer 'yes'. You won't be able to go further in the application for the second contract. If by chance you do and they find out, you will miss out on both and probably will be barred. Best not to risk it.
As far as response times, this has been covered previously. Give it anything from an hour to 3 weeks. They are really busy right now. Even LGW has been re-advertised internally again, so things must be pretty bad.