You should avoid non-Catholic homeschool groups, especially those that actively promote heresy. As to the first group you mentioned, I'm curious as to the content of the "decree of faith." Surely, Our Lord Jesus Christ is the Savior, but He is also the Second Person of the Blessed Trinity. I wonder if the faith decree mentions that at all.
The second group, which promotes the Westminster Confession of Faith - is one you should not participate in.
Very quickly, here are some errors of the Confession:
Chapter I (Of the Holy Scripture) - "The infallible rule of interpretation of Scripture is the Scripture itself: and therefore, when there is a question about the true and full sense of any Scripture (which is not manifold, but one), it must be searched and known by other places that speak more clearly."
- This article repudiates the teaching authority of the Church, and the chapter as a whole rules out the unwritten word of God, viz. Divine Tradition.
Chapter III (Of God's Eternal Decree) - "By the decree of God, for the manifestation of His glory, some men and angels are predestinated unto everlasting life; and others foreordained to everlasting death."
- If here it is suggested that God has created men for the purpose
of sending them to hell, then it is a heretical statement. Double-predestination was condemned at the Second Council of Orange (in A.D. 529).
Chapter XI (Of Justification)... read Session VI of the Council of Trent to see why this chapter is false.
Chapter XVI (Of Good Works) - "Works done by unregenerate men, although for the matter of them they may be things which God commands; and of good use both to themselves and others... they are therefore sinful and cannot please God."
- This opinion was condemned by Pope St. Pius V in Ex Omnibus Afflictionibus
(n. 35; 1 October 1567).
Chapter XXV (Of the Church) - "There is no other head of the Church but the Lord Jesus Christ. Nor can the Pope of Rome, in any sense, be head thereof
; but is that Antichrist, that man of sin, and son of perdition, that exalts himself, in the Church, against Christ and all that is called God."
- Do I need to point out the obvious error here?
Chapter XXVII (Of the Sacraments) - "There are only two sacraments ordained by Christ our Lord in the Gospel; that is to say, Baptism, and the Supper of the Lord"
- False because, on the contrary, Our Lord instituted seven
sacraments: Baptism, the Holy Eucharist, Confirmation, Penance, Extreme Unction, Holy Orders and Holy Matrimony.
Chapter XXXI (Synods and Councils) - "All synods or councils, since the apostles' times, whether general or particular, may err; and many have erred. Therefore they are not to be made the rule of faith, or practice; but to be used as a help in both."
- To suggest that general (ecumenical) councils may err - in defining doctrine - is simply heretical, and it is also false to say that they cannot be considered as the rule of faith.
Here is the Westminster Confession of Faith online: http://www.reformed.org/documents/wcf_with_proofs/