Without renouncing to PRs
Also, the 2 other kids who have PRs are 11 and 8 years old. If we stay in Canada for 6 months and then application to renew visitior's visa of the youngest child will be denied, could it be helpful to write that the Twovolder kids already got used to Canadian school so for children's best is to stay in Canada.
You need to understand that there are so many variables that may or may not happen,
nobody here can say for sure what any final result will be.
You may be reported upon entry to Canada for not meeting RO, or you may not.
If RO detected you may have your H&C reasons accepted by CBSA, you may not.
You may have your child's visitor status extensions all accepted, you may not.
If reported or RO violation later discovered and you appeal you may eventually win your appeal on H&C grounds, or you may not.
Everything is unpredictable, so the only way to know for sure is to try and see what happens. There are many things that can go wrong here with negative results, so it's important you know what can potentially happen and be prepared if things don't work out.