Not wise to do so.

If you are principal applicant, it's not wise.
1) No pay stubs to show (monthly)
2) No permanent position
3) Lack of proof for work in similar/same field

Excerted from Murthy Chat:

Attorney Murthy : On an EAD, a person is generally allowed to start a business entity and work for that entity or be self-employed, especially if one is in the dependent status. If the principal is on the EAD, it is safest to stay and work for the sponsoring employer, or, if using AC21 portability, to find a "same or similar" job and work as an employee, rather than taking a risk and being self-employed since the law does not seem to allow an independent contractor status for the principal applicant at the time of getting the GC approved.