-First, copy of your degree cert. will do, but have it authenticated from your embassy.

-Second,(E4 is right) Immigration is not interested w/ your degree.

-Third, (nathan is right too), Degree certificates will goes to Labor Dept. for evaluation of your job title to process your visa.

-Fourth, "shuttering carpenter"-no probs, provided that you have an invitation letter from the company. Let your company here resolve this for you..

-Fifth, yes! business visa can be converted into work visa. Again, its your company task to get the visa done.

-Sixth, Wish you Good luck! & advance warm welcome to Doha;)))