Your explanation is perfect!
If the exercises are not already part of Masher sequences, then it is
possible to write a script to compile them all, but that might be very
tricky if you have used custom source files. This part of undoc.txt
explains how you might do this:
Using the command-line switch /V7, you can automatically run a Hot
Potato, passing it the name of a file to open, and the name of a
configuration file, an HTML file to export to, the path to source files
you want to use, and the "next exercise" URL, and have the program
create standard version 7 output then close automatically without
showing its screen at all. Here's an example:
c:\HotPotatoes6\JCloze.exe /V7 c:\MyHotPotFiles\gapfill.jcl
c:\HotPotatoes7\source nextexercise.htm /s
This will silently run JCloze, open the file "gapfill.jcl", export it to
create a V7 web page called "gapfill.htm", then exit without even
showing its splash screen (the final /s suppresses the splash screen).
For JMatch and JMix, /V7Drag will create a drag-drop output, and for
JMatch only, /V7Flash will create a flashcard exercise.
Generally, though, I think it would be better to recreate each file
separately so you can test them as you go. You can never be sure the
search-and-replace has found exactly what was expected and produced
exactly what you want.