What breed is the dark kitten in the picture? I ask because he looks like he could possibly be mixed with a main coon or Norwegian forest cat. I also want to know how to determine a kittens eye color.
I presume they are littermates. You perhaps even know their parents? If so, it should be possible to know what breed they belong to, or at least, what look alikes they are...
The darkish darling may end up as a Maine Coon look alike, but its too early as yet to know.
And the same with eye color on very young kittens. They are usually all blue or bluish... Begins to change color at roughly week 6-7.
I agree that Maine Coon lookalike is a likely outcome. It will be easier to tell once they’re a bit older. Since he is a brown tabby, his eyes will most likely be green or amber.