"And by the way: the dinosaurs didn’t all die. Noah must have taken some with them."
What do you think he loaded all of the other animals onto the ark for? Food for the dinosaurs, obviously!
"They show up in too many works of ancient and “native” art."
Ancient people dug in the ground.
Ancient people found large skeletons.
Ancient people wondered, "What the holy fuck is that?"
Ancient people drew depictions of the bones with skin/muscle from the knowledge they have of how extant creatures look/behave.
Creationists come along and point to art as "eyewitness accounts."
Modern people laugh at creationists.
"And some of them are alive today."
Some of their descendants are alive today and various species that were around at the time of the dinosaurs are alive today.
Dinosaurs themselves--not so much.
"We’ve got a pod of them in Lake Champlain, Vermont, and the Canadians have them in Lake Okanagan, BC. There was a pod of them in Loch Ness, but I wouldn’t be surprised if they’re all dead by now, because that lake is so disgustingly polluted."
Then where are all of the dead Nessies washing ashore?
"We had dragons throughout Western Europe, until the medieval knights hunted them to extinction."
"Dragons" in the West were symbolic of Satan. The Good Christian knight's slaying of the "Dragon" was symbolic of Christ's/God's victory/power over Satan.
"The dragons in China lasted a little longer; Marco Polo saw one of them."
Dragons in the East, from what I understand, were representative of elemental forces of nature.
Marco Polo often liked to repeat hearsay without telling you he was doing so. While, from what I understand, he actually made the journey, much of what he wrote about came from tales travelers told him and not personal experience.