A really ambitious project would incorporate Grievous in all 3 somehow, like the guy who made him Maul.
Maybe…there is a way to incorporate grievous even earlier. Maybe into the ATOC droid army. Or even further into the Neomoidian army as a lowly TK4 Roger Roger droid who wants to be more.
Or even more ambitious…make him Darth Jar Jar after all.
If I had the deepfake skills, I would edit in Maul and Grievous and Dooku to meet.
Grievous could be leading the droid army in TPM in his natural Kaleesh form, then shows up rebuilt in AotC after being aboard the Donut when it explodes. Really, though, any such additions are beyond any of our skills.
Really, the most we could hope for is maybe adding him to the background of the Separatist meeting in AotC.