Yes, I believe that is the right family.A challenge at every Census. :-) In 1870, William and sister Hannah apparently orphaned and living with the Lippincotts in Springfield, William listed as "apprentice to farmer" at age "16".Same year, Lydia is in an odd housing situation, listed as a 13 year old "domestic servant" with a young minister and his family, and 3 single women in their 40s and 50s with no listed occupation other than "at home."William and Hannah were orphans at this point - but not Lydia. Must have been pure economics that placed her in another's home as a domestic servant.
1870 doesn't give us street addresses, but it would appear these two houses may have been a mile or so apart. Perhaps these two young domestic workers found each other there - in any case they were married 6 years later.