Re: (#1) The Implications and Applications of Article I. of the Augsburg Confession; one may be interested in following a similar discussion that is taking place at Concordia: The Lutheran Confessions, in their third roundtable discussion.

The roundtable begins by taking a look at the issue of individuals, churches, and the church. The roundtable cites a phrase from Article I. in the Latin, stating that the doctrine of the Trinity must be "believed without any doubt." Regarding doubt, the point is made that the doctrine of the Trinity is a divine mystery, certainly transcending the ability of complete human comprehension; yet there is no doubt but that our churches teach and confess this doctrine. Weedon makes the observation in the comments, that the intention of the Lutherans was "to communicate to the papal party at Augsburg that the Trinitarian orthodoxy of the Lutheran parishes was beyond dispute". (That is, the Lutheran princes should not be outlawed by the emperor for harboring those who teach or hold to heretical doctrines of the Trinity.)

CR notes: If the Trinitarian orthodoxy of the churches of the Augsburg Confession was to be unquestionable, then the individuals of those churches - Pastors, Professors, congregations, and people - could neither teach nor hold to any understanding of the Trinity which was not agreeable to the decree of the Council of Nicaea or the understanding of the Fathers (as specified with reference to the term "persons"); this was the standard to which they held themselves. Their orthodoxy would be called into question if it could be demonstrated that there were some among them who taught, preached, or believed strange (read: heretical) doctrines about God - such as that there are two principles, one good and one evil; that the Father alone is God and the divinity of the Son and the Spirit might be explained away; etc. (The chain is only as strong as its weakest link.)