I'm fairly certain my drake is going to be more interested in the female CHICKENS over the ducks.
He's been with them since day 1 and is pretty flock bound. Maybe if I put him in with the duck hens in their own enclosure for a month he'll straighten up. The Duck hens seem to make flirty eyes at him, though, and try to follow him around. But the 2 month old chicken pullets will try to jump up and scratch the duck hens away.
Sorry bout the toddler fight there OP. From what I've read, Given the choice, I believe that a pekin will choose a pekin to mate, but if potential mates are few, he'll make due with whatever duck is available. I was reading up on it when determining if I wanted more muscovies or a mix of breeds.
There is also a meat birds board on this forum, you can find it in the menu at the top of this page. I have read quite a bit there as well. There are quite a few chicken topics you need to scroll through but you can find duck, muscovy, and "mules" topics, or use the search feature.
I decided I am getting more muscovies, and will keep the parents as pets but want to let them raise their own babies for food.
My duck didn't start laying till her 10 month birthday, I think that's actually a little late. She started laying about 2 weeks after I gave her an old covered cat litter pan with straw in it. Your new girls are likely ready to lay, but new surroundings could interrupt them. Find some enclosed container, a litter pan, a cat crate with no door, something about that size for them to nest in. And if they know you'll let them out, they might hide their eggs if they find a cozy spot outside.