A second attempt to respond to your post, Peter ... Blogger ate the first one, so I will try to keep this one leaner and less appetising to the lurking nemesis. Without knowing where you intend to go with Pt2, I want to pick you up on two points so far.
1. You read this text as affirming that “our sexual behaviour ... impinges on our salvation.” This is true only to the extent that other offences on Paul’s several lists in Chapters 5 and 6 carry exactly the same consequences. Broadly speaking, those offences are matters of sexual behaviour (mostly heterosexual) and financial/economic oppression. I want to suggest that even these do not comprise an exclusive list of danger areas, but are included in this part of the epistle as a response to the particular presenting issues before Paul – the forbidden relationship between a man and his step mother, the court case(s) between fellow Christians, and some tolerance of the use of prostitutes. Paul’s rhetoric against these abuses includes condemning them by association with other sexual and economic wrongdoing. There is no suggestion that salvation is not imperilled by other classes of sins, and indeed idolatry and pride find their way into his condemnation, by association. My point then is this, that this text cannot be cited to single out sexual sins as specially perilous as you appear to be doing here. [PRC: Agreed.]
2. Your discussion of possible meanings for the key terms naming homosexual relations makes one thing clear – that the meanings of these terms, as Paul used them, is not clear at all! What does this portend for our discussion of homosexuality? How can an unclear text guide us towards the mind of God? I submit that there is a clear answer ... that we do not need to concern ourselves with the exact meanings of any of the terms in these lists of sins. Now let me explain myself:-
a) It is no easier to determine just what Paul meant by greed or robbery than it is to decipher the exact meaning of his sexual terms, but that does not lessen the impact of his warning regarding them.
b) His warning does not refer to these sins in their particular nature, but to sin in general. Sin is incompatible with salvation. Each of these particular sins is an abuse of our duty to love God and/or our neighbour, and none of them is a victimless crime. In each case, the Christians involved should have known better, and their failure to act out their faith is what puts their salvation at risk.
c) This is where my argument gets really Anglican, appealing to the tradition of Hooker, Sanderson, et. al. Any attempt to derive moral theology from the scriptures involves a fusion of at least two things: an exegetical process of reading the text to ascertain what it most probably meant in its original context; and a “reading” of our own particular social context to determine the facts on the ground to which the scripture may speak. As the two contexts, separated by 2000 years of cultural change, will have differences as well as similarities, finding the mind of God for today involves a transforming process of reasoning, prayer and consultation (as in Rom 12:1-2). One part of this process that cannot be bypassed is the “facts on the ground” investigation. Specifically, if we are considering homosexual relationships, then we need to find out what is happening in such relationships today, in our own context, among faithful Christians. Those facts, as we find them, are far more significant than what was happening among homosexuals in Paul’s day (which is why Lambeth 2008 called in vain for conservatives to engage in respectful conversations with gay Christians, as had happened among a minority of bishops at that conference). To know whether our economic arrangements constitute greed or theft, in the light of Paul’s warning, we need to examine the facts of modern life, asking whether we are loving our neighbours as ourselves. Similarly, a Christian ethic of homosexuality can only be derived from considering the facts of life as lived out by our brothers and sisters committed to faithful same-sex relationships. [PRC: The words 'can only be derived' is a very strong statement limited, apparently, engagement with what Scripture says.]