I forgot to add that the coop is probably too small for that many birds. 3 to 5 square feet is the minimum recommended amount. If I were you, I would either make it bigger or sell some of your birds.
If possible, divide up the coop and run for a while so they can see but not hurt each other. Honestly, I think the older hens are going to be overwhelmed by that number of new birds, so it's going to be chaos no matter what you do. It's going to be stressful for the birds and you can expect...
There is no way to tell at this age. Keep your eyes on comb size and color. Larger/redder combs coming in early means you have a boy. 6 weeks old is about the right time to start determining gender unless you get an obvious boy earlier.
Americana is just a hatchery word for Easter eggers. Ameraucanas are spelled differently and are purebred. Also quite expensive. They only come in a few colors, and your bird isn't one of them. They will also never have green or yellow legs. Easter eggers can lay many different colors of eggs...
It's an Easter egger. Can't see the comb well, but I think it is a pullet based on plumage color/pattern.
Would need good, clear photos of the silikies' combs to have a go at telling their genders.
Gosh, that's horrible. I'm sorry you've had that experience. For most it is just the combs. With some, like partridge Cochins and silver Phoenix, males and females have different coloring, but that's not true in most color varieties.
1 is looking like a probably cockerel. Not sure of the breed. Maybe splash Rosecomb bantam.
2 Porcelain D'Uccle cockerel.
3 Millie Fleur D'Uccle cockerel.
4 Partridge Cochin cockerel.
5 Rhode Island red bantam cockerel.
6 Probably a barred rock bantam cockerel, going by color. Comb isn't...