Credal, have to do with the creed and the associated councils (that Rome never attended because they were heretical at the time). Credal matters have to do with the Trinity, the existence of the Church and the resurrection of the body (although believing in the resurrection is not grounds for denying cremation or even forcing it into cemetaries, that is practice and pastoral). Evangelical communion is not real because they don't believe it to be, but that is practice, not dogma.