Sounds like the offer is for you to be here on single status and living in a labour camp in Ras Laffan. I'm not sure there is even an option for you to bring your family here looking at the offer if this is the case. I would confirm if the camp is in Doha or Ras Laffan or Mesaieed. You better confirm if you want your family here before you accept. And confirm exactly what family status entitles you to. The may not be willing to change your status to family once your here because they are keeping their cost low by having you in a labour camp. But if they switch you to family, they will have to pay separate for accommodation, transport, etc.
And as I'm sure you know, once you're here there is no job transfer.