My mom gets pension and the money is part of their savings from pension and job that they had 5-8 years ago. Bank statements from past 3-6 months should be enough to depict this? There is no business or any other source of income for them.
3 months' bank statements are inadequate. Financials are only one component of the visa application.
So, you conclude that TRV is good option or Super Visa in this case?
Unfortunately, IMO, your parents have weak applications. Based on the details you've shared, they don't have strong ties to their home country. Both Super visas/TRV applicants must prove they have strong reasons to return home.
1. Your parents are retired/ not employed/ don't have a business = No employment ties to return to
2. They don't have property or a lease agreement = Nil immovable assets to return to
3. They don't have dependent family = Family ties to Canada will be stronger/imbalanced to those in their home country = Possibility of overstaying
4. NZ General Visitor Visas are usually issued for 3 months. As your parents have NZ visitor visas which are valid until next year i.e. beyond 3 months, they must have been granted longer duration visas for some special reason. For example, if one of your siblings/their children live in NZ.
And, would their NZ visas be valid when they apply for a Canada TRVs?
You haven't posted too many details. It's difficult to advise on bits and pieces of information. You may want to post the comprehensive list of documents that you intend to submit for each parent + their individual situation/what you believe could help to strengthen their case
