I've been reading this post with interest. Being a Langton myself, im very interested in this family, and ive been researching the name for a week or two. Previous information i have is from my father and other family members who researched the name several years ago.
I know that my direct decendants come from Portsmouth, and before that from Newbury, Berkshire. Specifically Speen, just outside Newbury. The family seems to have moved there around 1679 when my ancestors William Langton married Elizabeth Gibbs, that year.
Previous to that i have much of the information you have, some other details too, and by the sounds of things a few issues with at least one George.
I know there is a George and Alice Holloway as i have read a record on it, in which the Manor of Shrevenham [Shrivenham] is passed to her, in 1678. However, i did suspect this George as father of George who married Mary Tyndale, was not right. Given your information David, i know believe Alice Holloway married George, son of William, who married Anne Stonehouse, then Katherine Fisher. This ties in with some other evidence I have, which I wont go into right now, as it will be an essay.
These Langtons (at least some of them) were living in Radley, Berks, not far from newbury a few decades before my William and Elizabeth. I'm convinced there is a link, i just need to find it, to complete my line into this main family.
Susan, I will email you, but David I didnt see your email address? I would love to share information with you both. And David, where can i get copies of your book?