Rose Constance probably should be Marie Rose de Lina Constant. May help in tracking. Vt Census for 1860 lists Mary Jalbert and her children on page 47 in Enosburhg, VT. You may have already seen this but the birth place for the chidren is given as VT. Albert age 20 born Canada Mariette age 17 born VT William Simon age 15 born VT Eli age 13 born VT Thomas age 10 born VT No Jean Baptiste is listed, he probable was working elsewhere. There should be some record in the VT Vital Records which can be checked in Middlesex, VT or at the library of the VT. French-Canadian Genealogcal Society in Colchester VT. When checking the records look under Jalbert, Gilbert. Gilbar, Who knows what an english speaker heard when the recording took place.
William Simon was married at St Matthew church which is Episcopal. This may make the records harder to find if you try to track through baptismal records.