Hello Ofonzo.
Major questions are base on area of concern.
But generally your sister will be asked where she works and dates. What her spouse does in Canada and place of work and position. Date of birth of spouse, if there are previous marriages please let her know details ( why the separation, date of divorce, how long was the marriage etc). Date of proposal, date of marriage, I wasn't asked details about children but I think you should know details because you maybe asked if any. Need to be truthful and let IO know If there are visa refusals. Address of spouse, date of your marriage. How and when you met. Dates of visits. Etc.
She need to know details about her spouse. I believe she will be fine with this.