In the cross you show, yes the barring gene is coming from the father, so all the chicks inherit it. (Barring gene is what makes them Crele, instead of just being colored like Welsummers.)
For the opposite cross, with Welsummer rooster and Crested Cream Legbar hens, the sons will have white...
To get sexlinks from a Welsummer rooster:
--any black hen with white barring will give one kind of sexlinks. The sons will be black with white barring (light spot on top of the head at hatch), the daughters will be black with no white barring (no light spot on top of the head.) Possible hen...
Black chicks, chance of some red/gold leakage as they grow up, white soles on the feet, lay brown eggs (shade midway between the parent breeds.)
Kinda yes.
http://kippenjungle.nl/breeds/crossbreeds.html
You can select breeds from a dropdown list (but it does not have all colors of all breeds)...
The only common one I know of is Olive Eggers, from crossing a Welsummer with a blue-layer or green-layer.
The other crosses are not common enough to have special names of their own. Of course you can name them in the obvious fashion: Welsummer/Leghorn, Welsummer-Orpington Mix, etc.
Crossing...