[PuxaVida]

Diffraction is solely aperture based.

Yes, but the effects of diffraction on the image depends on the sensor characteristics; like the size of the pixels, CoC and the diameter of the airy disk. The diffraction limited f-value is different in cropped sensor and FF sensor (given that they have the same MPs).

But generally speaking, the diffraction effects on the IMAGE for FF and APS-C are similar when you use equivalent f-values and equivalent fields of view.

By "equivalent" if you mean F=10@1,5x crop vs. F=15@FF, you're right. I have to correct myself here. Because,



1,5x crop, 50mm, 10 meters distance, F=10 have the same DoF in meters as in FF, 75mm, 10 meters distance, F=15. And at the same time F10 and F15 are diffraction limited f-values for 1,5x crop and FF sensor (given that they're both 12mp).