I checked the tax lists for the years 1836, 1838, and 1839, and found that William Weaver is listed as owning chattel goods, which would have been horse/cattle. He is not listed as owning property. You are correct that that part of Hocking County was origionally part of Fairfield County. When Hocking County was formed that section of Fairfield County became Marion Township, Hocking County.
My sugestion is to try the 1840 Hocking County census records. I do not have copies of them at home. I did check the death index 1867-1908 and found NO William Weaver.
Jacob MIller is listed as owning chattle goods in 1836, but no chattels in 1839---but he did own property in section 14
There is a Jacob Miller listed in the death index in book 1 page 24: year between 1867-1873: there are 2 Jacob Miller in book 2,--one 1885 page 13, and Jacob 1892 page 49. The index does not give me more complete data. You could contact the Records Dept., Court House, 51 E. Main Street, Logan Ohio 43138 The cost for these documents are $2.00 each. They are 2 pages each, and have the birth and death information, township, cause of death , but probally not the parents since the men were adults. There are 3 Jacob Millers listed in the 1870 census, but they are from the south western townships, not Marion. There is no William Weaver. Hope this helps somewhat.Kay