Yes, you could buy some point-of-lay pullets now and introduce a cockerel at any point really. If the hens were mature you would need to make sure that he was also mature enough to stand up to them. Otherwise he may end up hen pecked and be too afraid to do his job!
I am not sure of the exact number but she has hatched dozens of eggs and ended up with one hen and one cockerel. She has put them under reliable broodies and used an incubator in an attempt to get a good hatch.She told me that she only once saw POL pullets for sale. There were only two available and they were in Devon - a long drive from us. She was tempted but didnt go in the end.
One batch of eggs were successful but the resulting hens were either a cross or poor examples of the breed.
I am not sure if she has just been unlucky or if it is a result of in breeding. I know that ordering eggs to be delivered by post is not ideal anyway but she has done this with other breeds and had good results and same here with quail.