Found them in the 1870 Hopkinton, RI and 1880 Uxbridge, MA census records. Wife in 1870 census is recorded as Lella by Ancestry, but looks more like Cilla.Hard to connect this with Philomene, but children do have a good match.
I haven't linked this family yet. So I don't have any information on Napoleon. Considering the eldest Joseph Peter/Pierre Fontaine was born in Canada, I would guess they were married in Canada.
One possible family marriage is Joseph Lafontaine and Philomene Philibotte, married 12-Dec-1858 in Ste-Cecile, Milton, Shefford, QC.I don't have any children for them. So I never made a connection on what happened to them. Also don't have birth dates, so I cannot match birth years with census records. This is the closest I can get to this family.