I believe the Legbar is the mother. The specking in the breast makes me think he's split for mottling, so the Jubilee Orpington is probably the father, plus the white/pink Shanks are a good clue since white/pink shanks are dominant over yellow legs.
But both of those are gold, so they should only produce gold chicks. The cockerel looks silver to me.
So he'd be Silver Duckwing Barred(Crele), Mottled Split.
I agree that he is Silver, but that should not be possible from a cross of Cream Legbar hen x Jubilee Orpington rooster. So I think you are wrong about at least one parent.
blue egg..( blue egg layers are blue ameraucana, 2 crested cream legbars, and 1 Easter egger ( but based on size shape doubt it was hers - lighter and since she is a couple years old much older her eggs are bigger)
I would expect the Legbars to produce chicks that show a crest, and I do not see a crest on that cockerel.
I would expect Ameraucanas to produce chicks that show muff/beard on the face, and that have a pea comb. I would also expect their chicks to be black or blue all over, rather than showing a pattern of several colors like this cockerel shows.
If the Easter Egger really did not lay the egg, then I will guess that one of the Cream Legbars is the mother, because that has fewer problems (missing crest) than if a Blue Ameraucana was the mother.
Or there is a chance the Easter Egger actually is the mother, and laid an egg that does not look normal for her (since I don't know her coloring, comb type, or other traits, I can't tell how likely that is.)
I have the following roosters ( golden sebright, sebrightxegger cross) jubilee orpington, splash ameraucana , and a deleware
He appears to have barring, which means at least one parent must have barring. If the Legbar is his mother, that accounts for it. Otherwise the Delaware would be the most likely father.
I do not think the Splash Ameraucana could be the father. The cockerel appears to show black but not blue in his coloring (splash can produce blue chicks or splash chicks, depending on the color of the other parent, but never black chicks.) The Splash Ameraucana should also produce chicks that have muff/beard, pea comb, and are blue all over (not showing a pattern of several colors.)
If the mother is the Cream Legbar, then the Silver cockerel cannot have a gold father, which rules out the Golden Sebright and the Jubilee Orpington.
That leaves the possibility of the Sebright x egger cross, or the Delaware.
blue egg layers are... 1 Easter egger ( but based on size shape doubt it was hers - lighter and since she is a couple years old much older her eggs are bigger)
I have the following roosters...sebrightxegger cross
Pictures of the Easter Egger hen and the Sebright x egger cross might be helpful.