Thank you everyone! You have been most helpful.
Tall Al - the holes you have found are some that we have found as well. I do not know much more about his wife Mary (that could be them at Tan y Foel), other than she was born around 1833 in Llangeinwen, Anglesey. I can see them in the census records in the Village of Brynsiencen in the 1861 census, and at 19 Well Street in Gerlan in the 1871 census, with children Thomas, Evan, Mary, Owen, Emmanuel, and Robert John. In the 1881 census, they are at 16 Goronwy St., Gerlan, with Thomas, (son Evan passed away in 1873) Mary, Owen, Emmanuel, Robert, and Evan (7 years old). 1891 the family is at the same address, with Evan, Mary, Emmanuel, Robert, and Evan living in the home.
I have not yet traced her back before the 1861 census, or she and Evan (GGG) after the 1891 census. I do think it may be them in the 1901 census at Tan y Foel, so I'll continue digging into that. His son Evan (my GG Grandfather), no wonder I am confused, married Elizabeth sometime between the 1891 and 1901 in Gerlan. In 1901 I have Evan and Elizabeth, along with Evan Thomas Evans, Maggie M, and Robert John (my Great Grandfather) at 6 Goronwy St. in Gerlan. In the 1911 census they are at 54 Cilhaul Terrace in Mountain Ash, Glamorgan.
I have Evan Evans (GGG) death record from 1904, but no mention of Mary. Most of the men are listed as Quarrymen, possibly/probably working at Penrhyn at some point, which may have been their motivation to move south. I am hoping to get to the Gwynedd Records office to look at the Penrhyn documents - would like to confirm that they worked there, and what their involvement was in the strikes.
On our ancestry tree, it shows Evan Evans (GG) as having a death date of 1940 in Mountain Ash, Wales. I do not see any supporting documentation there, but it is possible.
Thank you for your help! Let me know if there is any other info that would be helpful and I will try to fill in what we know if possible, but I don't think I have much more than what is above.
Heather