A sex link hen can and will lay eggs that are capable of hatching. They chicks however will not be sex linked and they can be all over the place look wise.
#2 if there's a will there's a way.
That's a nice selection of birds. My temps are similar but I've never been able to coax much out of my birds in the winter without additional light (not heat), My Wyandottes are probably my poorest layers (4/week) but they are some of the most striking hens so I will not be without. Make your...