So it's a 6 horse FPTP race, eh?
If Canada had preferential voting, I wonder how those votes would go on a 2 party preferred basis? Not sure whethr NDC, PPC or Bloc would support conservatives, but I presume Greens would support the Liberals?
The NDP has traditionally been the party that, in a minority government, been able to persuade the party in power to support a few of the NDP causes. The reason?
Because despite Harper stating that elections would happen every four years, x number of days after Thanksgiving (2nd Monday in October), it is still possible for a new election to happen at any time. Trudeau's mandate from the 2019 election still had over 2 years to run before he would have had to call an election. He did this because he's gambling that he'll get enough seats for a majority government plus a comfortable enough margin that he can tell his opponents where to go and what to do when they get there. There have been scandals over shady shenanigans involving charities, there are other ethics - related stuff going on, and of course he just can't win no matter what he says or does regarding the pandemic. It didn't help that his own wife brought Covid back to Canada from the UK, when she, Margaret, and her daughter, Ella-Grace, attended an international women's event. Sophie had to isolate and the rest of the family did as well. Justin started working from their home at Rideau Cottage, rather than in the House, and the Reformacons accused him of "hiding." Well, he was doing the responsible thing, but you can't convince his opponents of that.
The advantage the NDP has in a minority government situation is to simply tell the Prime Minister that if he/his party do not support some particular bill or policy the NDP want passed, or if they do something the NDP doesn't support, the NDP will vote against the next budget or other money bill. If a money bill fails to pass, it's a vote of non-confidence in the government, the government falls, and an election is triggered. This can happen no matter how far into the mandate the PM is. Some governments have lasted less than a year, as happened in 1979 when Joe Clark's Progressive Conservative government fell. The Liberals were leaderless at the time, Pierre Trudeau having stepped down after losing to Clark, and they hadn't had time for a leadership convention yet. So the Liberals asked Pierre to come back, he hemmed, hawed, thought it over, and decided okay, but he had his own agenda he wanted to pursue - and that was repatriating the Constitution from Britain and creating the Charter of Rights and Freedoms.
The Liberals won the next election, and governed until 1984 (Trudeau had stepped down again, giving his now-famous "long walk in the snow" speech; that phrase has now entered the Canadian lexicon for when a leader should quit) and the Liberal PM at that time was John Turner; his time in office was so short that people have a tendency to forget it even happened. Lyin' Brian won the election in 1984, with a huge majority that meant he could do whatever he wanted. Even if all the opposition parties got together to oppose him (ie. vote down the budget), it was mathematically impossible to beat him.
This is the danger of huge majorities. If there's no way the government side can be beaten, they can do immense damage.
As for the idea that there are 6 parties in this race for forming the government, that's not ever going to happen.
First of all, the Bloc Quebecois is a regional separatist party that only runs candidates in Quebec. It is mathematically impossible for the BQ to form the government unless a bizarrely high number of other candidates run as independents and can't form an official party (there's a minimum number of seats required, and the BQ hasn't always met that minimum).
Second of all, Maxime Bernier is delusional. His party will go nowhere.
Third of all, it seems that the only time the Greens ever get anywhere is when Elizabeth May is the leader. One of her political fatal flaws is that she possesses a sense of ethics. Back in 2015, people were desperate to get rid of Harper, so the ABC movement came about: Anybody But Conservatives. The idea was to vote strategically - vote for the non-Reformacon candidate in your riding that has the best chance of winning, no matter if it's a party you wouldn't normally support. And Elizabeth May understood that in certain ridings, this would only result in splitting the left-wing vote so she tried to persuade the Liberals and NDP to not run candidates in ridings where the Green candidate would have the best chance of defeating the Conservative candidate and she would reciprocate.
The Liberals stuck their collective noses in the air and said no. I think there might have been one or two ridings where the NDP accepted her proposal; I don't remember.
When the dust settled on election night and Trudeau won, there were people who thought Justin should extend an olive branch to Elizabeth May and invite her to join his cabinet, as Minister of Science. This went out on social media and was a popular idea for a few days, and both Trudeau and May were diplomatically gracious about saying no. May thanked the people for their confidence in her, but said that no cabinet position had been offered (it's actually not against the rules to do this, just extremely unusual), and if it were, she would have to decline as it would mean having to support some Liberal positions on various issues that did not agree with the Green Party's positions on them.
In general, I would expect the Greens to support the Liberals.