小白兔，pjiang等高手: question about using EAD for a part time job

Currently I'm teaching full time on an H1-B. But if I use EAD to do a part-time contract job, is my H1-B still valid? Or I'm on "adjustment of status" and teaching job also has to use EAD? The part-time job is so attractive that I plan to take some risk.

My 485 has been pending over a year, they said they're doing "additional reviews" now. If my 485 got rejected, what is the worst case? Reapplying H1-B from China?

Any information is highly appreciated!