As we know spellings changed over time. I like using the "nickname" field and the "overview" field for AKA's (also known as) to reflect the transition, and use the most historically accurate for the "name fields."
Another option is the "display name" field - I like using it for prefix titles such as Governor, General, etc.
Are we reasonably sure that Raynall and Reynell are the same?
Another idea particularly on a shift that may get argued with is to use the "curator note."
By the way, DON'T merge two master profiles verified to actually be the same. I have to take off the MP tag of one of them first.