Well, as you can see, even an English word can be spelled more than one way if you read words phonetically.
I can't tell you how many Baptismal records I've read where the priest writes the child's name on the side of the record and again within the text of the record and spelled the name more than one way in the entry. (Probably many hundreds)
I have seen Sedillo spelled Cedios or with a Z. I finally gave up trying to stick to "one way". It doesn't really matter -- if you phonetically sound out the written name and come up with Sedillos (or Luzero or Montolla or Sanches) you are probably on the right track.
Anyway, there are many Sedillos in Lincoln County. The migration pattern seems to generally follow this pattern.
Santa Fe (early to mid 1700's)to San Miguel County - then some went to Lincoln by the mid to late 1870's -or-
Another group from Rio Abajo (Valencia and/or Socorro county) started moving to Lincoln County by 1868 (earliest baptismal records). The period of Mexican control of New Mexico has been the most difficult time period for me to research. The Spanish priests took great records, but something seemed to happen about 1840's (Gadsen purchase). I know that Lincoln County had land to offer people and many homesteaded there.
My Sedillo relative was Marcos Sedillo who was married to my great Aunt Beatrice Vigil. Marcos was from Manzano in about 1912. His parents were Juan Pablo Sedillo and Refugia Trujillo.
Jose Simon Sedillos bap. 28 oct 1831, age 4 days; son of Jose Ramos Sedillos and Ma Josefa Duran of Savinal; Godparents were Jose Benito Chaves and Maria Guadalupe Montoya is the only Simon (or Cimon) listed in the Our Lady of Belen Baptisms 1810-1851. No Francisca Molina listed
Good luck -- Martha Sanchez Wilson