I would not recommend adding just one Silkie. They are very different from other breeds. They rarely roost (they can't fly) so they need another Silkie to cuddle up with on the floor, or in my case, I stacked two, 2x4s on the floor of the coop so they can get off the soiled litter at night. Even then, I have to put them on it every night. They aren't the smartest birds!
I am new to them, so maybe Chiqita can voice her opinion about them since she has had them longer.
Sounds like you are having fun planning on adding more breeds!