Well, I'm amazed your turkey gal is still sitting....which may end in another day or two.
Of the risks, it will be the eggs that have the greater risk as the hen will at some point want to get up with the poults and teach them turkey things rather than sit on eggs.
If the weather is warm enough, and you have food and water nearby, the poults will likely take care of themselves returning to momma for warm ups...which could disturb the duck eggs, especially during hatching.
So if it were me, I'd be inclined to take the duck eggs and finish them out in the incubator to protect them from abandonment when momma gets up to care for the poults or from crushing when they are trying to hatch.
It could work...but I can see some pit falls.
LofMc