I see
Since you don't want them hatching in your current nest boxes, you have two options:
1. Build new ones and place them in the coop
2. Let them go broody in your current ones and then transfer them wherever you want
I will say though, inexperienced hens often give up after being moved, you usually have to wait a couple of days for them to fully go into broody mode, and then move them, but you still take a risk, and your chances are far lower because of their age
I say, go for early summer hatching or next year
You can try late summer to early spring, but especially if it gets cold quickly in your area, I wouldn't recommend it. As I've said a bunch of times by now, inexperienced mothers might not be so good at keeping their eggs and then their chicks warm, and during those months that can be a death sentence.
I will say though, I might make it sound like letting a younger inexperienced hen brood is the worst thing you can possibly do, but for a hen to become experienced she needs to gain it

So don't become totally discouraged from letting your hens hatched, I am just trying to highlight the risks so that you can prepare