You would get splash lavenders and blue lavenders. Both would be different from blue, splash, or lavender. I’m not sure about splash lavenders, but blue lavenders basically look like silvery splashes without the spots.
Self blue x blue would be 50% blue and 50% black (both split to self blue). This is because self blue is black with two copies of the lavender gene, so it acts like black when crossed with non-lavender varieties.