In ancestry, put T J McCan in the search box for AR. There is only one and it is 1880 Nevada Co Boughton TWP. THey are all listed with just initials and hard really to get a C for Callie out of the enumerator's writing, but I believe this is the same family. You would know better having a list of the kids. TJ 31 AR MS AL ?? 21 TN TN TN MA (f) 5 J? (m) 4 J(m) 2
As far as the last name being Whitney, on the marriages the names are certainly spelled Whitley.That one census for Robert and Arabella(there wasn't 2 of them, either) is spelled Whitney.Once again, I believe the enumerator made a mistake.That was also Nevada Co 1880.
It could be speculated that the Robert in 1880 is Callie's full brother with this George (maybe middle named Wesley) as a half brother. Sarah first was married to a Whitley and then married a Murphy resulting in children from both marriages. This Sarah is George's mother and is also Robert Whitley's mother. Look at the 1880 Nevada Co for Robert Whitney, then the 1900 Rapides Parish LA for George Murphy. That is where she states she was born in TN.
Mary Majors was listed as Miss on the marriage license. I found that odd with someone of her age just getting married. I did look for her previously but did not have any luck.Why don't you send for her death certificate to see who her parents were. It would be a great find if they are truly related and would open doors for you to search further.I will try looking at her tomorrow and see if I can come up with anything.