Sorry to say that Burial records for St. Sannan's held at Gwent RO only go to 1915, so no luck there at the moment. Caerphilly CBC, Bereavement Services, 01495 235189 / 235225 should be able to help you. Bedwellty must have become a Municipal cemetery before 1918 !!
Good Luck, Gerry
PS. No sign of a headstone for Jane in M I's, but they only go to the early 1900's.