Dear Michele Bergin,
Sorry for the delayed response. I'm often traveling and I didn't see your post. I was in Lincoln in March and the researchers were not able to find anything conclusive on Katherine "Hutchinson" Walker so at this point, her surname is still not identified conclusively. It is and has been very frustrating. I have pulled out all the stops to solve this puzzle and have invested in outside research. No success. I hope someone else will take up the project and run with it. Should anyone else that is descended from Katherine and John Walker decide to take on this research project, please contact me directly and I will be happy to share what I've learned.
Appreciate the links above and thank you for your note.