Who is Lor San Tekka?

What a great actor to have in Star Wars: The Force Awakens Max von Sydow is. Back when he was announced, we were almost certain that he will end up portraying a Force user. It wasn’t so. As a matter of fact, his character is killed mere minutes (were there minutes at all?) after being introduced.
But who was he actually and why was he the one to have the map which leads to Luke Skywalker? Furthermore, if he had the map, why didn’t he use it until then? He surely must have known that the First Order will want to retrieve it.
The official description of his character says that Lor San Tekka was a scout of some sorts and so, given his age, we may assume that he will appear in some of the future spin-offs (maybe even in Rogue One). But the questions still remain, with some others following quickly (with the answers, most likely, being revealed in the spin-offs as well).
Why is there such familiarity between Kylo Ren and Lor San Tekka? Why does Lor say that general Organa is a princess? Ultimately, given the propaganda of the Empire, why did he sided with the Rebels and, afterwards, with the Resistance?
