Any comments, data or info will be greatly appreciated.
Thanks in advance.

There were several Ramon Cuellar's on a few different trees.
This family is one that began in the US when
Jose Ramon CUELLAR who had been born in Guerrero, Mexico on 21 August 1781 the son of Jose Jaoquin CUELLAR and Tomasa GUTIERREZ, moved to Wetzel in West Virginia and married Tereza GONZALEZ in 1805. Their son Domasio CUELLAR 1806-1859 married and had I think 5 sons;

1.Senovio Cuellar 1832,
2.Ramon Cuellar 1834,
3.*Jose Ramon Cuellar 1837,
4.Melesio Cuellar 1838 ? 1895
5.Concepcion J Cuellar 1841
and at least 2 of these went to Texas Concepcion was born in Texas and I think at some stage the whole family moved there although Damasio 1806-1859 died in Florida.

*Jose Ramon married Locadia and during his life he lived in Banquetto,Nueces, Texas and Duval, Texas
To his wife Locadia (sorry I don't know her maiden name) I can find 6
children all born in Texas:-

1.Damasio Cuellar 1860

2.Cipriana Cuellar 1863 m. Jesus YBANEZ

3.Emeterio Cuellar 1865-1935 m. Marcella MUNIZ 1888-1963 this couple had 12 children these are the names of some of them :-
Mariana Cuellar 1907 ? Ramon Cuellar 1907 ?
Guadalupe Cuellar 1909 ? Marcella Cuellar 1910 ?
Abel Cuellar 1911 ? Salvador Cuellar 1915 ? 1981

4.Cesario Cuellar 1868 ?

5.Victoriano Cuellar 1869-d: 1941 in Val Verde Texas

6.Jesus Cuellar 1871


The above is a bit of a mess, I'm not very good when it comes to US searches. It's difficult with just census records and I did not find an Isabel Cuellar or very much that I was sure about in the 1900s
Nevertheless here are a few things to look at that may aid you.

1870 United States Federal Census
1880 United States Federal Census
1910 United States Federal Census
1920 United States Federal Census
1930 United States Federal Census
U.S. Civil War Soldiers, 1861-1865
This data base has a few CUELLARs; RAUL N. LONGORIA'S GENEALOGY DATABASE
CUELLAR