It has been a long time, I hope all is well. I am not 100% positive but I believe Sidney was the daughter of David & Mary Evans. Sidney was born May 22, 1769, Manchester twp., York Co., Pa., and she died Mar. 21, 1821 and is buried at Warrington Mtg. If interested, I have a photo of her headstone.
I have M.B. Walmers book "100 Years at Warrington" and it lists nothing about Sidney Evans. At my local LDS Family History Library I have a permanent copy of the 1877 Abstracts of Warrington Meeting by Gilbert Cope. I am planning a trip there this week for another matter, and if you would like I'll check for any Evans minutes?
A couple of years ago I was in Pa. and I went to the CCHS and looked through the Albert Cook Myers Collection, where I found a birthdate for Isaac Cook, the husband of Sidney Evans, that throws a wrench into the mix. I copied the following word for word:
(Notes made by Albert Cook Myers) Carlisle, 6-16-1899
The following copied out of an old copied schoolbook, written by Jesse Cook. Original in posession of Elizabeth Walker who lives with her daughter Mrs. Thomas Mauls, Carlisle, Cumberland Co., Pa.
"The age of Isaac Cook son of Jesse Cook and Mary Cook. Isaac Cook was born 15th of the 6th 1766 in Warrington township York County and departed this life 10th Day of the 9th month 1831 he departed at the house of Jesse Cook his son in Latimore township, Adams county and was intered in Friends burying ground at Warrington Meetinghouse on the 11th of the same month aged 65 years 2 months 25 days by Jesse Cook his son."
I don't know what to make of it or how to explain it. Isaac may have been born illegitimate...