Sorry I have not got back to you. I tried to match your information to mine and found that there were too many discrepancies. I have James Cross Killip's son Thomas being born in 1922 and marrying an Ann Callow in Cumberland. However, if your information comes from 19c letters, it looks like it my information that is in error. I certainly have Ann Christian Killip who joined the mormons and emigrated to US as a daughter of James C.
I am afraid I gave up and put your request on the back-burner. I don't have access to the detail you have from the US censuses and perhaps such information might help me to correct my info and match your ancestors to the correct Killip line. There might be info in the letters too that may help. If you could send me any such information, I will then work on it when received. If you want to send me anything my email address is available by clicking on my name in the post heading (apologies if you know this!)