Ok! Actually Patrick (thank you Patrick), gave me a great idea.
I put all the new strings that I was going to substitute at the top of the JSON file.
Then I ran a search of the “title”: string, and bookmarked each instance.
Then I ran a macro that:
Highlighted the first line of the document
Copied the line.
Deleted the line. (So the second one would jump up, and the data gets deleted as well)
Press F2 (to jump to the bookmark)
Highlight the line
Paste the line
Pressed CTRL + F2 (to unmark the line)
Pressed CTRL + Home (to go back to the top of the file)
Rinse and repeat!
Thank you again Patrick for giving me this idea!