Perhaps one way to answer this or resolve the various choices is to ask one question. Yes, the one question!
Which character knows himself best? Who has the greatest self-knowledge? I think that someone who is aware of his own weaknesses, desires, failings, strengths, and needs is likely someone who would be more aware of his own actions and temptations, and who would be more master of himself and less liable to the siren call of the Ring.
And then, who has the next strongest sense of self-awareness? And so on .... until we find the character who has the least or most undeveloped self-knowledge.
One reason why Boromir falls is that, while his heart is noble, he is so self-assured, has questioned himself and his actions so little, that he is unable to see what the Ring is doing to him. In contrast is Frodo, who constantly questions himself. (He thus is not "the weakest link"
Frodim (sic).
The problem with this idea, of course, is that it assumes every character is as well developed as any other in the Fellowship. Yet a stab can be made, no?
So, instead of a one anwer poll, we should be filling out a hierarchy. Sort of a Middle earth Maslow's hierarchy of needs, for those of you who know 7th Age psychology.
