Hi, welcome to BYC!
Seems like it might be stress causing your birds not to lay. Many stressors spread out so they never got to settle in completely...
I personally do not like layer feed. For birds who aren't laying, it's way too much calcium and can stunt growth as well as causing kidney issues which could include gout or failure. Since you are thinking of adding a roo, you might consider using an all flock type feed. Aside from the high calcium in layer I feel like the low protein content gives you a lot less room to budge. For example, when you add scratch it diminishes the protein further. And 16% is the bare minimum to support a layer, but not necessarily support healthy chick hatches. Though many will tell you they've never had problems and are probably telling the truth as they see it.
Why are you getting a rooster? If you've never experienced it, I suggest don't unless you have very specific goals especially in a flock the size of yours. For protection, to hatch chicks, just for fun? Still a bad idea if it's your first year raising chickens... sincerely!
I have a mixed age and gender flock. So I feed Purina Flock Raiser which is 20% protein and 1% calcium. Not saying it's the best but it is what's available at an affordable price that meets the nutritional need of my whole flock. I offer oyster shell free choice on the side for layers. The only time I ever get softees is when a new layer is just getting started and has to do with their reproductive system starting up or shutting down, not the feed.
Will you be quarantining your new comers? Yes, that will add another stress. But since you aren't getting eggs anyways, better to get it over with. @aart has good questions to help give appropriate suggestions as you move forward.
Couple of notes... they are not hens until 1 year old. Before that they are pullets. Same goes for boys... until 1 year are considered cockerels. There is a big difference between the two especially for boys. A good rooster might be nice, but a snotty little cock brings all the terrors of raising teenagers to the foreground!
Waiting on first eggs can be so hard!
You're almost there though!
One more question, do you supplement light?
