I find numerous Tidwells in 1790 Fairfield, SC (8 individual heads of household on a single image of the census), and added a few marriage and later census documents earlier today, but having problems making sense of this family group. Some of the children don't seem to fit well, and 2-3 of them were born after her death. The one born in Wales is particularly odd, since his birth followed that of a sibling born in Virginia.
"United States Census, 1790," database with images, FamilySearch (https://familysearch.org/ark:/61903/3:1:33SQ-GYBZ-4DR?cc=1803959&am... : 21 May 2015), South Carolina > Fairfield > Not Stated > image 3 of 56; citing NARA microfilm publication M637, (Washington D.C.: National Archives and Records Administration, n.d.).
https://www.familysearch.org/ark:/61903/3:1:33SQ-GYBZ-4DR?i=2&c...