It sounds like you know for sure that this is your Crecy on the 1910 census:
1910 Census - Jackson, Monroe County, Arkansas
James Orange - 35 - married 2 years - 2nd marriage - Ark-VA-LA
Crecy Orange - wife - 35 - md 2 years - 2nd mrg - mother of 6 kids, 4 now living - Ark-don't know-Ark
Lucinda Orange - dau - 15 - Ark-Ark-Ark
Milton Orange - son - 13 - Ark-Ark-Ark
Elnora Orange - dau - 11 - Ark-Ark-Ark
Nakomis Orange - son - 3 - Ark-Ark-Ark
So this census tells us that Crecy's marriage to James Orange (22 May 1908 in Monroe County, Ark) was her 2nd marriage. The marriage record you found on Ancestry is just the index, but FamilySearch has the image of the original document, which does indeed list her as Mrs. Creasey Smith: https://familysearch.org/pal:/MM9.3.1/TH-266-12051-214674-6?cc=1417439
So now let's look for her in 1900, 8 years before she married James Orange. This looks like her:
1900 Census - Jackson, Monroe County, Arkansas
Henry Smith - born July 1874 - 26 - married 6 years - Ark-Ark-Ark
Corra Smith - wife - born Nov 1879 - 21 - married 6 years - mother of 3 kids - Ark-Ark-Ark
Lucinda Smith - dau - May 1895 - 5 - Ark-Ark-Ark
Milton Smith - son - July 1897 - 2 - Ark-Ark-Ark
Irene Smith - dau - Nov 1900 - 3 mos - Ark-Ark-Ark
Corra may have been her middle name, or perhaps the census taker thought Creasy sounded like Corra. But looking at the kids' names, that must certainly be her. Irene is probably the same person as Elnora, and the children took the last name Orange when their mother married James Orange.
Which brings us back to the marriage of Creasy Mays to Henry Smith on 31 Jan 1894 in Monroe County, Ark... the original image of which is also on FamilySearch. This one doesn't have a "Mrs." before her name, which usually means she was a "Miss": https://familysearch.org/pal:/MM9.3.1/TH-266-11839-157891-26?cc=1417439
So it looks like your grandpa was correct, that Creasy's maiden name was Mays. So she *should* be Creasy (or Corra?) Mays on the 1880 census. The Creasy Mays you found in Alabama is the right age and right name, but that Creasy was born in Alabama and your Creasy is always listed as being born in Ark. And the Creesey in Phillips County, Arkansas is a Creesey Smith. That *could* be her, if she was using a different surname (like her children did, changing from Smith to Orange). But there's not enough evidence to prove either one is for sure your Creasy.
Hang on, I'm going to look around some more...
Okay, so here's a marriage for Creasy Orange to Jessie Johnson on 11 Jan 1914 in Monroe County, Ark:
https://familysearch.org/pal:/MM9.3.1/TH-267-11599-157817-94?cc=1417439
And this looks like them on the 1920 census in Jackson, Monroe County, Ark:
Jessie Johnson - 51 - Ark-GA-NC
Cresie Johnson - wife - 48 - Ark-Ark-Ark
Jessie Johnson - dau - 15 - Ark-Ark-Ark
Addie Johnson - son - 12 - Ark-Ark-Ark
Nacumba Smith - step-daughter - 15 - Ark-Ark-Ark
Do you know when & where Creacy died? If so, you could order a copy of her death certificate, which should list her parents' names (if the person who supplied the info knew their names).
Also, Creasy may be a nickname for Lucretia.