For NIW, you should stay in the same field before your I-485 get approved. It does not matter if you switch from a research position to a non-research position, such as engineering, as long as you are doing it is in the same field. I assume that your I-140 have already got approved. In case not yet, you should keep status of your quafications the same. For example, you should justify why a labor certification will hurt the national interest.
As long as you have submited your I-140 for NIW for one year, you can renew you H-1B after 6 years of H1B. If your have already submitted your I-485, EAD application is another option.
As long as you have submited your I-140 for NIW for one year, you can renew you H-1B after 6 years of H1B. If your have already submitted your I-485, EAD application is another option.
