Can i go for H1b premium processing even if i received RFE?

I have received RFE after 6 months for my H1B visa extension. In this case can i go for H1B premium processing?

Secondly, If my petition doesn’t get approve, is my visa stands rejected or cancel? In this case, Can i file visa from another project after going to India?

It can be upgraded to PP when the RFE response is submitted. If the petition is denied, then that is the end of the road. It cannot be used for any other employer and/or project.