HI Melanie,
I believe you are looking at this with the correct perspective of using Fusion as a automated "watch dog." Without getting into specifics, since I am unaware of how your instance is set up, the basics of building a Fusions scenario would be the following.
1) Create two separate scenarios; one to monitor Project Due Dates and one to monitor Project Condition (or similar field, if not using Condition).
2) Start both with a Watch Event module looking at the target object and field.
3) Create you scenario to determine what data to pull, what data to change (if necessary), and what action you need taken (email/notification).
4) You can create custom emails in Fusion to be sent with specific language. ie. "We are notifying you (the requestor) that the Due Date of you project has been changed...."
5) Once built, set your scenario as always on. Or if you are trying to keep the scenario runs down, set to run at a specific time (i.e. EOD, at Midnight, twice daily, etc.)
I'd suggest signing up for the Fusion Bootcamp. While it is basic information, it's a great start and intro to Fusion and the various modules you can use. Reach out to the community for Tips and Tricks. There may also be others who can give their time to walk through a couple scenarios they've built and share with you.
I hope this helps.
Best,
Joaquin