Let's not cloud the issue with facts, ha ha.
I saw a copy of the marriage info for Daniel Waller and Nancy and his initial is listed as H. The transcription for Daniel and Lucy Long shows his middle initial as M.
I'm pretty certain we're dealing with two different Daniels. Daniel H is the son of James Waller and Susan McCoy. I'm not sure who Daniel M belongs to though I'm willing to bet he's from the same clan. As for name similarities I'll let the below items speak for themselves.
1) Daniel H is on 2 different census reports (1860 and 1870) as the son of James and Susan.
2) That there are 2 different Robert Wallers who are sons of Daniel Waller is not surprising. Why?
A) The Wallers have a tendency to repeat names.
1a) There are 5 different Leroy Theophilus Wallers - all related.
Aa) 2 of these LT Wallers were born within 7 years of each other and died within 5 years of each other. They were both doctors. My LT is the son of James Monroe. The other is the son of Colombus Arastus. Both seem to be named after the original LT - son of James and Susan.
2a) James and Susan had a son named James M. and Elbert and Mary had a son named James M. Both pretty close to each other in age. One James M. served in an AR unit in the war and my James M was in the 31st LA.
Who is Elbert D Waller? He is certainly kin to James (born 1808) though I'm not sure if cousin or brother with a different mother. They moved together or pretty close from Hancock, GA to Chamber Cty, AL and then on to Columbia Cty, AR. Both Elbert and James's children settled in Claiborne/Webster Parish, LA and Columbia Cty, AR. One of Susan's kin, a McCoy, performed the marriage ceremony for Elbert and Mary. Elbert was in Hilliard's Legion. Enough of him for now.
3a) I think it's entirely possible that Lucy and new hubby moved to TX around the same time as James M was here in the late 1800s though James went to Grayson and Hopkins counties - where his LT was born. I'll assume Daniel M died young as divorce was not nearly as common as it became in the 20th century, especially in our family.
4a) Leroy pops up again as my grandfather's middle name. Even odds it's come up again for others in this clan.
3) Robert Lee Waller (son of Daniel and Lucy) only shows Dan Waller on his death cert. which makes paternity difficult to pin on Daniel H. I will accept that he's related based on all of the above plus a couple more tidbits.
A) He died in the same age range as My grandfather and great-grandfather and of the same cause. My dad is 75 and expects the same thing any day. The original James died at 74 and I suspect of the same thing. (the sons who went to war all died a bit younger.
4) Hilliard's Legion.
A) Elbert and at least one son served in this AL unit.
B) Hilliards and Wares were in the same unit.
C) James and Elbert had kin who married into those families.
Where am I going with this?
D) There is a Clark(Clarke) Waller in the legion who doesn't seem to belong to James and Elbert though it's a good chance he's related. Again, this is a large family. Could Daniel M trace back to him somehow?
I don't hold with Waller/Sackwell as being the parents of James. In a geneological library here in Houston I found a book with Bible records transcribed that show James Waller and Elizabeth Ellis as his parents. I think it's called Georgia Pioneers or Geneologies of … Author is Shepherd I think. I made a copy and when I can find it again we may all get to see it.
If this has raised new doubts there is always the Waller DNA project. How much it will help in this case I can't say.
This geneology business can be tricky.