Engineer or manager is fine both will allow you to sponsor your family if your salary is ok( more than 7.000 QAR) .

You can change your occupation on RP later but it will take long time and you will be required to bring a lot of documents from your side and from the company side as well and u have to change your contract and many other things.. beside you have to change it from 2 places ,, Labor office first ,, then immigration ..... BUT …

You can simply ask the company to change the visa they have from Engineer or supervisor to Marketing Manager..

it will take just 3 days without any more requirements . it’s so easy for everybody to do it this way ,, if the company reject to do that you must know they don’t want to give you that position.
good louck