Ooof. You've taken on a task and a half. And furthermore, I suspect, one that already has a 3rd party solution; particularly for specific products (like Mozilla).
1. I doubt whether all bug fixes boil down to a simple "either/or" choice. Indeed, some may involve several 'fixes' that have to be implemented at once.
2. I'm afraid that nobody is going through a list of bug fixes (of which there may be thousands) to determine which one is "right" for you. And even if some kind soul did: What if they're WRONG?
I have a feeling that you're going to need to (a) re-think your approach, or (b) lower your sights.
Isn't it funny how there's always time and money enough to do it WRONG?