Question: Did the Montreal Canadiens ever have exclusive rights to players from Quebec?
Prior to the 1960s, there was no NHL amateur draft. The recruitment of prospects was simply a matter of first come, first served. The Montreal Canadiens ensured they were first served by establishing perhaps the greatest farm system in sports history, with junior and senior teams on the prairies, minor pro teams in the U.S. and entire leagues in Quebec. The Leafs operated a similar network in Ontario and beyond. All players signed to those teams remained the exclusive propoerty of the NHL "sponsor" team until they were released or traded.
Prior to 1967, the Leafs and Canadiens held a further advantage. According to A Thinking Man's Guide to Pro Hockey, by Gerry Eskenazi, published in 1973, each NHL franchise had exclusive rights to players within its 50-mile territorial limits. So the Leafs and Canadiens could browse the neighbourhood rinks near Toronto and Montreal at their leisure, while the Rangers had a lock on the next great goalie from Hoboken.
Most of these advantages disappeared in 1963 with the introduction of the amateur draft. But the Leafs and Canadiens continued to benefit from players developed under the old system well into the 1970s.