Canadian with US PR card wanting to move home with US born kids

[VanIslandGirlinNC]

I met and married my US husband in 1999 and moved to the US to be with him. I have my permanent residence card but have not become a US citizen. We are wanting to move to Canada and need some advice. Our 3 children are US born and from what I understand because I am a born Canadian my children have dual citizenship. We have paperwork coming to us to apply for their Canadian citizenship papers right now but were told that it can take over 6 months to file and receive them. I was told by the Canada Passport office that I do not need passports to bring my children over the border (just original birth certificates), but every website that I have seen regarding border crossing says that they need either a passport or US passport card. What do I really need? I was also told that with my permanent residence card and my birth certificate (and old expired Canadian passport) I shouldn't have a problem going home. Is this true? And here's the most complicated part, my husband is unsure whether he can get a passport or US Passport card because he has some child support payments in arears and was told that there's a chance that he wouldn't be able to go anywhere out of the country. We were planning on filing for his residence once we were all in BC, but I don't know what the best step would be. My mom is very anxious for us to move back up to live with her since she's having medical problems and is by herself. I would appreciate any and all advice. Thank you.