How long will I need to keep them locked up before I can let them free range?
Since the drake will have his own girls, will he bother my chickens?
I would keep them penned a couple weeks. Even then especially if you have a body of water close by they still may find it.
I'd keep them in there at least a few days and maybe only feed them in the am and again at night so they are used to that. Also get them used to you being the treat person (peas or some other small/easy snack) so they will start to realize you are the holder of food and treats and if they want them, they come to you.
Then let them out for a bit and hang out with them and get them back to their pen with food and/or peas.
Then let them explore a bit more on their own and use food/peas to get them back where you need them.
The drake could still bother your chickens, so keep an eye on him. He may be fine and leave them alone.