So are we to understand "salvation" in the WLC as specifically referring to sanctification and not conversion?
In the case of infants, the faithful use of the means of grace by believing parents in their child's interest
precedes his conversion. Glorification
follows sanctification. Sacraments are
emblems of divine grace, which begins for his elect in eternity past, and encompasses eternal life for them.
The salvation in view, witnessed to in the sacraments, is comprehensive. Westminster's language is intended to put the reader into a comprehensive appreciation of the blessing. This idea is completely in accord with the 3FU's presentation:
Heidelberg Cat. Question 66
Q. What are the sacraments?
A. The sacraments are holy, visible signs and seals. They were instituted by God so that by their use He might the more fully declare and seal to us the promise of the gospel. And this is the promise: that God graciously grants us forgiveness of sins and everlasting life because of the one sacrifice of Christ accomplished on the cross.
Heidelberg Cat. Question 67
Q. Are both the Word and the sacraments then intended to focus our faith on the sacrifice of Jesus Christ on the cross as the only ground of our salvation?
A. Yes, indeed. The Holy Spirit teaches us in the gospel and assures us by the sacraments that our entire salvation rests on Christ's one sacrifice for us on the cross.
Belgic Confession Article 33 - The Sacraments
We believe that our gracious God, mindful of our insensitivity and infirmity, has ordained sacraments to seal His promises to us and to be pledges of His good will and grace towards us. He did so to nourish and sustain our faith. He has added these to the Word of the gospel to represent better to our external senses both what He declares to us in His Word and what He does inwardly in our hearts. Thus He confirms to us the salvation which He imparts to us. Sacraments are visible signs and seals of something internal and invisible, by means of which God works in us through the power of the Holy Spirit. Therefore the signs are not void and meaningless so that they deceive us. For Jesus Christ is their truth; apart from Him they would be nothing. Moreover, we are satisfied with the number of sacraments which Christ our Master has instituted for us, namely, two: the sacrament of baptism and the holy supper of Jesus Christ.
The Westminster
Confession (which is not to be divorced from the catechetical expressions) does not use the term "means" in the chapter on Sacraments, ch.27. However, it does use the language of "means" and "ordinary." In particular, recall that the Reformed and Presbyterian churches teach that the sacraments are intended to strengthen and assure us in faith.
Chapter 18: Of Assurance of Grace and Salvation
18:3 This infallible assurance doth not so belong to the essence of faith, but that a true believer may wait long, and conflict with many difficulties before he be a partaker of it: yet, being enabled by the Spirit to know the things which are freely given him of God, he may without extraordinary revelation, in the right use of ordinary means, attain thereunto. And therefore it is the duty of everyone to give all diligence to make his calling and election sure; that thereby his heart may be enlarged in peace and joy in the Holy Ghost, in love and thankfulness to God, and in strength and cheerfulness in the duties of obedience, the proper fruits of this assurance: so far is it from inclining men to looseness.
Chapter 17: Of the Perseverance of the Saints
17:3 Nevertheless, they may, through the temptations of Satan and of the world, the prevalency of corruption remaining in them, and the neglect of the means of their preservation, fall into grievous sins; and, for a time, continue therein: whereby they incur God’s displeasure, and grieve His Holy Spirit, come to be deprived of some measure of their graces and comforts, have their hearts hardened, and their consciences wounded, hurt and scandalize others, and bring temporal judgments upon themselves.
Chapter 3: Of God’s Eternal Decree
3:6 As God hath appointed the elect unto glory, so hath He, by the eternal and most free purpose of His will, fore-ordained all the means thereunto. Wherefore they who are elected, being fallen in Adam, are redeemed by Christ, are effectually called unto faith in Christ by His Spirit working in due season, are justified, adopted, sanctified, and kept by His power through faith unto salvation. Neither are any other redeemed by Christ, effectually called, justified, adopted, sanctified, and saved, but the elect only.
Chapter 1: Of the Holy Scripture
1:7 All things in Scripture are not alike in plain in themselves, nor alike clear unto all: yet those things which are necessary to be known, believed, and observed for salvation, are so clearly propounded and opened in some place of Scripture or other, that not only the learned, but the unlearned, in a due use of the ordinary means, may attain unto a sufficient understanding of them.