Thanks for your letter. If your William Pitt was born about 1821 (ours was born in Dec. of 1820- pretty close) and if he was born in Kidderminster, then I suspect there is a high likelihood that we are talking about the same man.
Since we come from his sister, I have not tried to follow his family any further but I do have some of his ancestry before him. All that I have is in the Ancestral File in Salt Lake, as you have seen. I hope it does you some good. You might want to check the actual parish records for Kidderminster to verify for yourself that this is really the same family but it surely seems likely.
I descend from Ann Pitt, a sister just older than your William. The names she gave her children are very similar to the names your William gave his children and they are the same as used by their ancestors repeatedly. Ann named her children: Thomas, Edwin, Ann, Mary, Elizabeth and Ellen. The name of Francis was also common in the family and was probably the real name of the "Frank" listed on your chart as a son of William.
I hope what I have provided is helpful. Check out the Kidderminster Parish records. Also, if you know of any wills of parents, uncles, aunts. etc. they can often confirm family relationships.
Our Ann Pitt married Edwin Keysell and had a family in the Kidderminster area. She died fairly young and he raised the children before he too died fairly young. Their daughter, Mary Keysell then married an Irishman, Alexander Lindsay, who was also an orphan and serving in the British Army. When they married, they had nothing and so responded to a call from Britain to colonize New Zealand and obtain free land as homesteaders there. This was right after the Maori uprisings there and Britain wanted the land tamed for future expansion. These were my Father's grandparents and he knew them quite well. They sailed to NZ in the 1870s with one little baby boy. My Grandmother was born in NZ in 1882. The family did quite well there and built up a large dairy operation. Eventually they sold out and moved to Oregon, USA in 1903 when Grandma was 21. She here married my Grandpa and had Dad in 1914 and I came along in 1950. So, that is how our family got separated from Kidderminster.
Thanks for writing.
Best of luck to you, Cousin