Is it safe to make uncooked beef cannelloni with cheese and eggs, stuff the raw shells and leave in fridge overnight? I would put the hot tomatoe sauce over top just before baking.
Is the meat cooked or not ? it's not clear.
I would prepare the stuffing, cook it all and cool it down and stuff the cannelloni and put that in the fridge.
Personally, I would bake it all, sauce included the day before and cool it down and put that in the fridge. (I treat that the same as a lasagna).
It is fine to assemble the dish ahead of time, as long as it is cooked thoroughly when you finish it.
The hazard would be making sure it is done, since it will start from cold, but if you check (beef is easy to visually tell if it is cooked) and see the meat has turned brown and there are no bloody juices in the pan, then you will be fine.
Remember, too, many people order rare or medium rare hamburgers and steaks. If the meat is fresh, and the assembled dish is refrigerated, there is nothing to worry about.
It's safest to cook everything except the pasta. Assemble the dish, cool, cover and refrigerate overnight. Make sure you bring the dish up to room temp prior to baking. It should take ~30 minutes to prevent having your dish burst from thermal/temperature shock.
Note: The pasta will absorb moisture overnight and the finished dish will be "al dente".