I believe Margaret E Wright was Miss ME Alexander age 17 when she married WW Wright age 24 Aug 8 1878 in Sevier Co. I have not located them on the 1880 census but did find the Savall sons in Montgomery Co AR 1900 with the McKelroy family.
www.familysearch.org has a James Monroe Savall as son of John Savall and Margaret E. Alexander b Nov 15 1893. They state he was b in Garland Co and died in Garland Co.There is an entry in the Buckville Cem in Garland Co for Margaret E Savall b Jun 9 1861-Apr 12 1899.
There is no William Wright in the Sevier Co bk that would fit yours. There may be something on the Sevier Co usgenweb site, though. Also, looking at the 1870 census Sevier Co, I see a 9yr old Margaret Alexander in the house of a James Wright b abt 1830 MS.
My ggggrandfather was James Walker Wright, I am related to these families, but there are far too many Williams and James to keep them sorted out. I do not know which James that one is on the 1870.