If crossing into Canada near Niagara Falls, I would suggest the Lewiston Bridge as the best location versus Fort Erie or the Rainbow Bridge.
It is a newer facility and I find the process smoother there.
You will need a passport for the child and there has been some talk about the parent "not" signing a passport for a young child. You should ask an official and confirm that point.
We cross regularly and the only recommendation on food is: no citrus fruits, no lamb products including in any pet foods, no eggs.
We have had zero issue with bringing in beef, pork, poultry or fish.
We are regularly boarded by a guard who is simply looking to see if we are hiding anyone in the RV.
You will need vet papers for your pet.
There have been many posts about brining firearms into Canada.
Leave them at home.
Welcome to Canada and hope you enjoy your visit.
2014 Fleetwood Southwind 32VS 🇨🇦