I re-highlighted a couple of words Anthony.
Is this what you meant by ambiguous:
ambiguous
1. having more than one meaning: having more than one possible meaning or interpretation
an ambiguous response
2. causing uncertainty: causing uncertainty or confusion
an ambiguous result
Microsoft® Encarta® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.
I believe the 1st definition is what Peter J. Wallace seems to be saying in "Whose Meaning? The Question of Original Intent":
It is interesting to note that wherever they could, they found ways of allowing for a diversity of views among sound Reformed men. They did this by adopting wording that could be interpreted in different ways.
I do not believe Wallace is correct. They did not intend the WCF to be "interpreted in different ways" but to be carefully silent on points where there was no clear consensus.
They would not have wanted to be ambiguous and make it easy for readers to "read into" the text what they wanted to get out of it. If that were the case, then the FV guys could easily be considered confessional.