Too early to tell gender. The feather growth is normal. For some reason, the lavender color often produces birds with shredded looking feathers. In here we call it the shredder gene. As far as I know, no one is really sure what causes it.
I think you're right about the mother. The chick lacks the white head spot that would indicate barring. It is silver based, and I would guess the father is silver based as well.
I think so. You should know soon. Cochin males tend to color up early in their combs.
Blue Cochins are not as rare as lavender, but they're just as pretty. Lavender is lighter and more even in color than this chick. But it's just my opinion. Others may have other ideas.
The cream one could well be a Delaware or Delaware type broiler. The tan on seems too uneven in color to be a buff rock. It could be a red laced white Cornish if it has a pea comb.
It's the other two I meant with the original post. I'm just not sure on those two.