All Lourdes proves is that people believe in the power of a heavenly Christ.
You are completely (and probably deliberately) missing the point. The issue is not whether or not miracles are real or ghosts or witchcraft or magic or whatever. The issue is whether a historical event can occur which people watching interpret as a miracle or whatever. You said "All we have of Jesus is the impossible." Even if that were true, which it isn't, it wouldn't necessarily mean that Jesus is unhistorical or mythical.
Take Matt. 9:27-31. Obviously, this is an event which is magical or a miracle or whatever. Let's assume a scientific perspective and say that obviously Jesus didn't make any blind person see by some magical or holy power.
That doesn't mean that two people who were or claimed to be blind did not claim to see as a result of something Jesus did, and that bystanders interpreted it as a miracle.
I am not saying this particular even happened, simply that even if we only had miracle stories they could very well be stories of actual events people thought were miracles, whether they were the placebo effect or the tricks of a charlatan or whatever.
One can disbelieve or believe that the events reported as miracles in the gospels were miracles or not, or that they happened or not. But one cannot reasonably dispute that events like those in the gospels can happen in such a way that someone witnessing could interpret them as miracles, given that people have done so throughout recorded history.
So, I'll ask again, when are you going to start refuting the basic arguments I offered "one at a time?"