1. Nobody cares how "old" your family is but a Canadian citizen who leaves Canada keeps his citizenship unless they renounce it.
2. If you were born in Canada, you pass on citizenship to your children. You will need to apply for their citizenship cards, see http://www.cic.gc.ca/english/citizenship/proof-how.asp
With US passports and no citizenship cards, they are only tourists in Canada.
3. Canada and the US have an agreement concerning custody, child abduction etc. If you try to run to Canada to escape shared custody, your husband can request that authorities in Canada return your child. They can not make you go back if you don't want to but if you don't want to, they will take your child and send him to your husband. You need to win full custody or permission from your husband if you want to move with your child to Canada.
4. non-citizens do not get passports in Canada so I don't know what you mean. If you are a Canadian citizen, you can get a Canadian passport and it will look the same as any other Canadian passport. If you are also a US citizen, keep in mind that you must always file taxes in the US and you must use your US passport every time you enter the US.