It's not possible to guess the chances of TRV approvals for yourself and your children. It would depend on the purpose of your visit + your ties to your home country + your ability to afford the visit with your own finances + to some extent, on your previous travel history
You would also have to explain why your husband has been in Canada for almost 6 months and wants a trv extension. Given he has been in the country so long it may raise concerns that you plan on staying in Canada.