You are getting a lot of good advice here. I’ll wind up repeating some of it but maybe add my own twist.
Hatching is as straight run as you can get. Most of my hatches are closer to 2/3 one sex than 50-50. It can be either sex. One recent hatch was 14 pullets and 7 cockerels. Another was 2 pullets and 7 cockerels. I once got seven straight run chicks from a hatchery and got all pullets. It could have just as easily been all males. The more chicks you get the better your chances of getting pullets but it’s just odds.
I agree you need a plan to handle the cockerels. If you get the birds from a show-quality breeder the excess cockerels may not be that hard to sell, but normally it’s a case of giving them away. Once you no longer own them you no longer control them. Most will wind up being eaten.
With those breeds it’s hard to sex the chicks early. Many sexual traits can start to show up at around five weeks but I find Ameraucana to be especially difficult. I’m not familiar with Barnevelders but here is a link from someone that is.
This link takes you to a thread that talks about those traits that sometimes show up at 5 weeks. In my experience it is usually easier to say that this one will be a cockerel than it is that a certain one will be female. Some males show these traits a lot earlier than others.
How to sex chicks
How long can you brood chickens in the house? For as long as you can stand it. Some people have house chickens, keeping adults in the house. I don’t want to even imagine how that works. I have electricity in the coop so my chicks go straight there into a built-in brooder from the incubator or the post office, whether in the heat of summer or with outside temperatures below freezing.
I don’t know where you are or what the weather will be like when you get them, but most chicks can go outside around five weeks of age. Most chicks are fully feathered by that time and can handle the weather, but you might have special circumstances. I’ve had chicks go through nights without any heat at less than six weeks and the overnight low in the mid 20’s Fahrenheit. In a ridiculous heat wave a few years back I turned the daytime heat off at 2 days and the overnight heat off at 5 days. There is no set time, each brood is unique.
I certainly agree to get the coop built before you get the chicks. They grow awfully fast and life has a way of getting in the way of plans.