To me this is the heart of these scriptures, not so much the letter.
For the most part I would agree with you, but the phrasing you used gives me pause. Perhaps because I see James 1:5 misused so much.
Do I know Obama’s heart? No, but I do see his actions and his actions show he is NO Christian. The doctrines he espouses (like other cult members) show he is not a Christian.
I have no trouble stating that he is not, in the least, a Christian. If he were, if Christ changed him then Zero would not do what he does.
If he doesn’t live a Christian life then it is reasonable to conclude he is not a Christian.