Yes, fiancee can be included in application, since Canada recognizes Common-Law partners. But you will have to prove it.
There are things you should consider first. Your fiancee will have to go through everything you went (background checks, police certificates, medical, IELTS etc.). Does your fiancee have all his degrees and education certificates ready? All of this can delay your case. So, if you are not in hurry to move to Canada, you can have him added. But keep in mind that it can delay your processing a bit.
If you are not in hurry, then its better to include him now since, after marriage, spouse immigration will take even longer. If you include him now, it will be shorter processing for him, but longer processing for you.
And remember, if you get married before immigration, you MUST declare it. You cannot hide it after marriage. It will seriously go against you and may even revoke your PR. If you do not want to delay your case, postpone marriage until after PR.
I have summed all your options. Make a calculated choice.