It is interesting that the American revision of the WCF would eschew the latter half of the offending paragraph and take a tone much like that of the 2LC.
In their description of God in the first paragraph of these chapters, the WCF and Savoy are exactly the same, while the 2LC adds some detail with the language of "subsistence" and "essence" borrowed from the 1LC.
The chapters are, of course, very similar, but the 2LC has a consistent thematic departure: an emphasis on the wisdom of God.
This extends even to an understanding of the fall, one of the points in which the wording of the 2LC matches directly with the WCF and not with the Savoy.
The 2LC shares the references to union with Christ with the Savoy, along with an added reference in paragraph 8 of Chapter 8, where part of the work of Christ is to unite the believer to himself by his Spirit.
The 2LC also, in clarification of both the Savoy and WCF, states that "the principal acts of saving faith have immediate relation to Christ.
All three of these confessions affirm that Scripture is the authority that dictates Christian belief, but the 2LC goes a bit farther, taking content from the 1LC.
Whereas the WCF and Savoy explicitly affirm reason in their reference to deduction, the 2LC subtly allows reason while attempting to dilute it as a concurrent authority.
While these affirmations about Scripture run the risk of opening the door to what some might term bibliolatry, their purpose in the 2LC is to make clear to the reader that even ascription to this confession, as comprehensive as it is, does not guarantee all of the knowledge necessary for salvation and obedience.
The formulators of the 2LC did indeed use the WCF and Savoy as templates for their own confession because, in large part, they agreed with the overall narrative of salvation set forth in those documents.
1) Hereafter, the Westminster Confession will be referred to as the WCF, the Savoy Declaration as the Savoy, the 1689 London Confession as the 2LC, and the First London Confession as the 1LC.