Canada's shipbuilding industry is now, and has always been, capable of building just about anything Canada's military would need. And in 1972, as expensive as operating a 45-aircraft carrier would have unquestionably been, the ability was there. The Trudeau years saw the military just gutted, because Trudeau and his socialist ilk figured that the US nuclear umbrella and NATO would save them from attack, and that meant the Canadian forces didn't have to be much at all. Mulroney knew better than that, and the forces as a result in the 1980s had substantial plans. Hence Canada talking about SSNs. During the whole SSN buying debate, Canada did more than consider building the things themselves - they commissioned studies from their best shipbuilders on what that would cost. I don't think any designs came out of it, but I know they were working on it. I know because my dad was in on it. 
Overhauling Eagle would need to happen if they wanted a substantial operational life out of it. But since the Brits were gonna scrap it, it makes lots of sense to buy it from Britain for peanuts and rebuild it into a modern fleet carrier. That's pricey, but 1972 Canada had major unemployment problems and everybody wanted to fix that, and a defense-growing Conservative government with a communist-hating pro-spending NDP in support would not have a hard time finding the political will. The Liberals wouldn't like it, but the jobs gained in Ontario and Quebec from a growing Canadian military would provide the Conservatives political help anyways.
The fleet would most often use the four Iroquois class destroyers as escorts, though they'd want something to go with it, hence the Patrol Frigate program speeds up a fair bit. I also figure that the SSNs/SSKs would come anyways - we'd need to replace the Oberons eventually.
Overhauling Eagle would need to happen if they wanted a substantial operational life out of it. But since the Brits were gonna scrap it, it makes lots of sense to buy it from Britain for peanuts and rebuild it into a modern fleet carrier. That's pricey, but 1972 Canada had major unemployment problems and everybody wanted to fix that, and a defense-growing Conservative government with a communist-hating pro-spending NDP in support would not have a hard time finding the political will. The Liberals wouldn't like it, but the jobs gained in Ontario and Quebec from a growing Canadian military would provide the Conservatives political help anyways.
The fleet would most often use the four Iroquois class destroyers as escorts, though they'd want something to go with it, hence the Patrol Frigate program speeds up a fair bit. I also figure that the SSNs/SSKs would come anyways - we'd need to replace the Oberons eventually.